Phentermine Interactions

Drugs, Nutraceuticals and Supplements
Shown To Interact Negatively with Phentermine

This information should not be interpreted without the help of a healthcare provider. If you believe you are experiencing an interaction, contact a healthcare provider immediately. The absence of an interaction does not necessarily mean no interactions exist.

Approved Drugs

Nutraceuticals / Supplements

Approved Drugs

Drug	Interaction
Abaloparatide	The risk or severity of adverse effects can be increased when Phentermine is combined with Abaloparatide.
Abametapir	The serum concentration of Phentermine can be increased when it is combined with Abametapir.
Acarbose	The therapeutic efficacy of Acarbose can be increased when used in combination with Phentermine.
Acebutolol	The therapeutic efficacy of Acebutolol can be decreased when used in combination with Phentermine.
Aceclofenac	The risk or severity of hypertension can be increased when Phentermine is combined with Aceclofenac.
Acemetacin	The risk or severity of hypertension can be increased when Phentermine is combined with Acemetacin.
Acetazolamide	Acetazolamide may decrease the excretion rate of Phentermine which could result in a higher serum level.
Acetohexamide	The therapeutic efficacy of Acetohexamide can be increased when used in combination with Phentermine.
Acetophenazine	Acetophenazine may decrease the stimulatory activities of Phentermine.
Acetylsalicylic acid	The risk or severity of hypertension can be increased when Phentermine is combined with Acetylsalicylic acid.
Aclidinium	The risk or severity of Tachycardia can be increased when Phentermine is combined with Aclidinium.
Acrivastine	Phentermine may decrease the sedative and stimulatory activities of Acrivastine.
Adenosine	The risk or severity of Tachycardia can be increased when Phentermine is combined with Adenosine.
Albiglutide	The therapeutic efficacy of Albiglutide can be increased when used in combination with Phentermine.
Alclofenac	The risk or severity of hypertension can be increased when Phentermine is combined with Alclofenac.
Alfentanil	Phentermine may increase the analgesic activities of Alfentanil.
Alfuzosin	The therapeutic efficacy of Alfuzosin can be decreased when used in combination with Phentermine.
Alimemazine	Phentermine may decrease the sedative and stimulatory activities of Alimemazine.
Aliskiren	Phentermine may decrease the antihypertensive activities of Aliskiren.
Almasilate	The serum concentration of Phentermine can be increased when it is combined with Almasilate.
Almotriptan	The metabolism of Almotriptan can be decreased when combined with Phentermine.
Alogliptin	The therapeutic efficacy of Alogliptin can be increased when used in combination with Phentermine.
Aluminium phosphate	The serum concentration of Phentermine can be increased when it is combined with Aluminium phosphate.
Aluminum hydroxide	The serum concentration of Phentermine can be increased when it is combined with Aluminum hydroxide.
Amantadine	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Amantadine.
Ambrisentan	Phentermine may decrease the antihypertensive activities of Ambrisentan.
Aminophenazone	The risk or severity of hypertension can be increased when Phentermine is combined with Aminophenazone.
Aminophylline	The risk or severity of adverse effects can be increased when Phentermine is combined with Aminophylline.
Amisulpride	Amisulpride may decrease the stimulatory activities of Phentermine.
Amitriptyline	Phentermine may decrease the sedative and stimulatory activities of Amitriptyline.
Amitriptylinoxide	The therapeutic efficacy of Amitriptylinoxide can be increased when used in combination with Phentermine.
Amlodipine	Phentermine may decrease the antihypertensive activities of Amlodipine.
Ammonium chloride	The serum concentration of Phentermine can be decreased when it is combined with Ammonium chloride.
Amoxapine	Phentermine may decrease the sedative and stimulatory activities of Amoxapine.
Amphetamine	The risk or severity of serotonin syndrome can be increased when Amphetamine is combined with Phentermine.
Anagrelide	The risk or severity of Tachycardia can be increased when Phentermine is combined with Anagrelide.
Anisotropine methylbromide	The risk or severity of Tachycardia can be increased when Phentermine is combined with Anisotropine methylbromide.
Antazoline	Phentermine may decrease the sedative and stimulatory activities of Antazoline.
Antipyrine	The risk or severity of hypertension can be increased when Phentermine is combined with Antipyrine.
Antrafenine	The risk or severity of hypertension can be increased when Phentermine is combined with Antrafenine.
Apomorphine	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Apomorphine.
Arbutamine	The risk or severity of hypertension can be increased when Phentermine is combined with Arbutamine.
Arformoterol	The risk or severity of hypertension can be increased when Phentermine is combined with Arformoterol.
Aripiprazole	Phentermine may decrease the sedative and stimulatory activities of Aripiprazole.
Aripiprazole lauroxil	Phentermine may decrease the sedative and stimulatory activities of Aripiprazole lauroxil.
Armodafinil	The risk or severity of hypertension can be increased when Phentermine is combined with Armodafinil.
Ascorbic acid	The serum concentration of Phentermine can be decreased when it is combined with Ascorbic acid.
Asenapine	Phentermine may decrease the sedative and stimulatory activities of Asenapine.
Astemizole	Phentermine may decrease the sedative and stimulatory activities of Astemizole.
Atenolol	The therapeutic efficacy of Atenolol can be decreased when used in combination with Phentermine.
Atomoxetine	The risk or severity of hypertension can be increased when Atomoxetine is combined with Phentermine.
Atropine	The risk or severity of hypertension can be increased when Phentermine is combined with Atropine.
Azatadine	Phentermine may decrease the sedative and stimulatory activities of Azatadine.
Azelastine	Phentermine may decrease the sedative and stimulatory activities of Azelastine.
Azilsartan medoxomil	Phentermine may decrease the antihypertensive activities of Azilsartan medoxomil.
Balsalazide	The risk or severity of hypertension can be increased when Phentermine is combined with Balsalazide.
Benazepril	Phentermine may decrease the antihypertensive activities of Benazepril.
Bendroflumethiazide	Phentermine may decrease the antihypertensive activities of Bendroflumethiazide.
Benorilate	The risk or severity of hypertension can be increased when Phentermine is combined with Benorilate.
Benoxaprofen	The risk or severity of hypertension can be increased when Phentermine is combined with Benoxaprofen.
Benperidol	Benperidol may decrease the stimulatory activities of Phentermine.
Benzatropine	Phentermine may decrease the sedative and stimulatory activities of Benzatropine.
Benzhydrocodone	Phentermine may increase the analgesic activities of Benzhydrocodone.
Benzphetamine	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Benzphetamine.
Benzydamine	The risk or severity of hypertension can be increased when Phentermine is combined with Benzydamine.
Bepotastine	Phentermine may decrease the sedative and stimulatory activities of Bepotastine.
Bepridil	Phentermine may decrease the antihypertensive activities of Bepridil.
Betahistine	Phentermine may decrease the sedative and stimulatory activities of Betahistine.
Betaxolol	The therapeutic efficacy of Betaxolol can be decreased when used in combination with Phentermine.
Bethanidine	The risk or severity of hypertension can be increased when Phentermine is combined with Bethanidine.
Bilastine	Phentermine may decrease the sedative and stimulatory activities of Bilastine.
Biperiden	The risk or severity of Tachycardia can be increased when Phentermine is combined with Biperiden.
Bismuth subnitrate	The serum concentration of Phentermine can be increased when it is combined with Bismuth subnitrate.
Bisoprolol	The therapeutic efficacy of Bisoprolol can be decreased when used in combination with Phentermine.
Bosentan	Phentermine may decrease the antihypertensive activities of Bosentan.
Bretylium	The therapeutic efficacy of Bretylium can be decreased when used in combination with Phentermine.
Brexpiprazole	The therapeutic efficacy of Brexpiprazole can be decreased when used in combination with Phentermine.
Bromocriptine	The therapeutic efficacy of Bromocriptine can be increased when used in combination with Phentermine.
Bromotheophylline	The risk or severity of adverse effects can be increased when Phentermine is combined with Bromotheophylline.
Bromperidol	Bromperidol may decrease the stimulatory activities of Phentermine.
Brompheniramine	Phentermine may decrease the sedative and stimulatory activities of Brompheniramine.
Buclizine	Phentermine may decrease the sedative and stimulatory activities of Buclizine.
Bumadizone	The risk or severity of hypertension can be increased when Phentermine is combined with Bumadizone.
Buprenorphine	Phentermine may increase the analgesic activities of Buprenorphine.
Buspirone	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Buspirone.
Butaperazine	Butaperazine may decrease the stimulatory activities of Phentermine.
Butorphanol	Phentermine may increase the analgesic activities of Butorphanol.
Butriptyline	Phentermine may decrease the sedative and stimulatory activities of Butriptyline.
Butylscopolamine	The risk or severity of Tachycardia can be increased when Phentermine is combined with Butylscopolamine.
Cabergoline	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Cabergoline.
Caffeine	The risk or severity of adverse effects can be increased when Phentermine is combined with Caffeine.
Calcium ascorbate	The serum concentration of Phentermine can be decreased when it is combined with Calcium ascorbate.
Calcium carbonate	The serum concentration of Phentermine can be increased when it is combined with Calcium carbonate.
Canagliflozin	The therapeutic efficacy of Canagliflozin can be increased when used in combination with Phentermine.
Candesartan cilexetil	Phentermine may decrease the antihypertensive activities of Candesartan cilexetil.
Cannabidiol	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Cannabidiol.
Captopril	Phentermine may decrease the antihypertensive activities of Captopril.
Carbamazepine	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Carbamazepine.
Carbimazole	The risk or severity of adverse effects can be increased when Phentermine is combined with Carbimazole.
Carbinoxamine	Phentermine may decrease the sedative and stimulatory activities of Carbinoxamine.
Cariprazine	Phentermine may decrease the sedative and stimulatory activities of Cariprazine.
Carprofen	The risk or severity of hypertension can be increased when Phentermine is combined with Carprofen.
Carvedilol	The therapeutic efficacy of Carvedilol can be decreased when used in combination with Phentermine.
Celecoxib	The risk or severity of hypertension can be increased when Phentermine is combined with Celecoxib.
Celiprolol	The therapeutic efficacy of Celiprolol can be decreased when used in combination with Phentermine.
Cenobamate	The serum concentration of Phentermine can be decreased when it is combined with Cenobamate.
Cetirizine	Phentermine may decrease the sedative and stimulatory activities of Cetirizine.
Chlorcyclizine	Phentermine may decrease the sedative and stimulatory activities of Chlorcyclizine.
Chlorothiazide	Phentermine may decrease the antihypertensive activities of Chlorothiazide.
Chlorpheniramine	Phentermine may decrease the sedative and stimulatory activities of Chlorpheniramine.
Chlorpromazine	The therapeutic efficacy of Phentermine can be decreased when used in combination with Chlorpromazine.
Chlorpropamide	The therapeutic efficacy of Chlorpropamide can be increased when used in combination with Phentermine.
Chlorprothixene	Phentermine may decrease the sedative and stimulatory activities of Chlorprothixene.
Chlorthalidone	Phentermine may decrease the antihypertensive activities of Chlorthalidone.
Choline magnesium trisalicylate	The risk or severity of hypertension can be increased when Phentermine is combined with Choline magnesium trisalicylate.
Cilazapril	Phentermine may decrease the antihypertensive activities of Cilazapril.
Cilostazol	The risk or severity of Tachycardia can be increased when Phentermine is combined with Cilostazol.
Cimetidine	Phentermine may decrease the sedative and stimulatory activities of Cimetidine.
Cinnarizine	Phentermine may decrease the sedative and stimulatory activities of Cinnarizine.
Cisapride	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Cisapride.
Citalopram	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Citalopram.
Citric acid	The excretion of Phentermine can be decreased when combined with Citric acid.
Clemastine	Phentermine may decrease the sedative and stimulatory activities of Clemastine.
Clenbuterol	The risk or severity of adverse effects can be increased when Phentermine is combined with Clenbuterol.
Clidinium	The risk or severity of Tachycardia can be increased when Phentermine is combined with Clidinium.
Clofedanol	Phentermine may decrease the sedative and stimulatory activities of Clofedanol.
Clomipramine	The therapeutic efficacy of Clomipramine can be increased when used in combination with Phentermine.
Clonidine	Phentermine may decrease the antihypertensive activities of Clonidine.
Clothiapine	Clothiapine may decrease the stimulatory activities of Phentermine.
Clozapine	Phentermine may decrease the sedative and stimulatory activities of Clozapine.
Cocaine	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Cocaine.
Codeine	Phentermine may increase the analgesic activities of Codeine.
Cryptenamine	Phentermine may decrease the antihypertensive activities of Cryptenamine.
Cyclizine	Phentermine may decrease the sedative and stimulatory activities of Cyclizine.
Cyclobenzaprine	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Cyclobenzaprine.
Cyclopenthiazide	Phentermine may decrease the antihypertensive activities of Cyclopenthiazide.
Cyclosporine	The risk or severity of hypertension can be increased when Cyclosporine is combined with Phentermine.
Cyclothiazide	Phentermine may decrease the antihypertensive activities of Cyclothiazide.
Cycrimine	The risk or severity of Tachycardia can be increased when Phentermine is combined with Cycrimine.
Cyproheptadine	Phentermine may decrease the sedative and stimulatory activities of Cyproheptadine.
Dapagliflozin	The therapeutic efficacy of Dapagliflozin can be increased when used in combination with Phentermine.
Darifenacin	The risk or severity of Tachycardia can be increased when Phentermine is combined with Darifenacin.
Debrisoquine	Phentermine may decrease the antihypertensive activities of Debrisoquine.
Deserpidine	Phentermine may decrease the antihypertensive activities of Deserpidine.
Desflurane	The risk or severity of hypertension can be increased when Phentermine is combined with Desflurane.
Desipramine	Phentermine may decrease the sedative and stimulatory activities of Desipramine.
Desloratadine	Phentermine may decrease the sedative and stimulatory activities of Desloratadine.
Desmopressin	The risk or severity of hypertension can be increased when Desmopressin is combined with Phentermine.
Desvenlafaxine	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Desvenlafaxine.
Dexbrompheniramine	Phentermine may decrease the sedative and stimulatory activities of Dexbrompheniramine.
Dexchlorpheniramine maleate	Phentermine may decrease the sedative and stimulatory activities of Dexchlorpheniramine maleate.
Dexfenfluramine	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Dexfenfluramine.
Dexibuprofen	The risk or severity of hypertension can be increased when Phentermine is combined with Dexibuprofen.
Dexketoprofen	The risk or severity of hypertension can be increased when Phentermine is combined with Dexketoprofen.
Dexmedetomidine	The risk or severity of hypertension can be increased when Phentermine is combined with Dexmedetomidine.
Dexmethylphenidate	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Dexmethylphenidate.
Dextroamphetamine	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Dextroamphetamine.
Dextromethorphan	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Dextromethorphan.
Dextropropoxyphene	Phentermine may increase the analgesic activities of Dextropropoxyphene.
Dezocine	Phentermine may increase the analgesic activities of Dezocine.
Diamorphine	Phentermine may increase the analgesic activities of Diamorphine.
Diazoxide	Phentermine may decrease the antihypertensive activities of Diazoxide.
Dibenzepin	The therapeutic efficacy of Dibenzepin can be increased when used in combination with Phentermine.
Diclofenac	The risk or severity of hypertension can be increased when Phentermine is combined with Diclofenac.
Diclofenamide	Diclofenamide may decrease the excretion rate of Phentermine which could result in a higher serum level.
Dicyclomine	The risk or severity of Tachycardia can be increased when Phentermine is combined with Dicyclomine.
Diethylpropion	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Diethylpropion.
Diflunisal	The risk or severity of hypertension can be increased when Phentermine is combined with Diflunisal.
Dihydralazine	Phentermine may decrease the antihypertensive activities of Dihydralazine.
Dihydrocodeine	Phentermine may increase the analgesic activities of Dihydrocodeine.
Dihydroergocornine	The risk or severity of hypertension can be increased when Phentermine is combined with Dihydroergocornine.
Dihydroergocristine	The therapeutic efficacy of Dihydroergocristine can be decreased when used in combination with Phentermine.
Dihydroergotamine	The therapeutic efficacy of Dihydroergotamine can be decreased when used in combination with Phentermine.
Diltiazem	Phentermine may decrease the antihypertensive activities of Diltiazem.
Dimenhydrinate	Phentermine may decrease the sedative and stimulatory activities of Dimenhydrinate.
Dimetindene	Phentermine may decrease the sedative and stimulatory activities of Dimetindene.
Dimetotiazine	Phentermine may decrease the sedative and stimulatory activities of Dimetotiazine.
Diphemanil	The risk or severity of Tachycardia can be increased when Phentermine is combined with Diphemanil.
Diphenhydramine	Phentermine may decrease the sedative and stimulatory activities of Diphenhydramine.
Diphenidol	The risk or severity of Tachycardia can be increased when Phentermine is combined with Diphenidol.
Diphenoxylate	Phentermine may increase the analgesic activities of Diphenoxylate.
Diphenylpyraline	Phentermine may decrease the sedative and stimulatory activities of Diphenylpyraline.
Disopyramide	The therapeutic efficacy of Disopyramide can be increased when used in combination with Phentermine.
Disulfiram	The therapeutic efficacy of Phentermine can be decreased when used in combination with Disulfiram.
DL-Methylephedrine	The risk or severity of hypertension can be increased when Phentermine is combined with DL-Methylephedrine.
Dobutamine	The risk or severity of adverse effects can be increased when Phentermine is combined with Dobutamine.
Dolasetron	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Dolasetron.
Dopamine	The metabolism of Dopamine can be decreased when combined with Phentermine.
Dopexamine	The risk or severity of hypertension can be increased when Phentermine is combined with Dopexamine.
Dosulepin	Phentermine may decrease the sedative and stimulatory activities of Dosulepin.
Doxapram	The risk or severity of hypertension can be increased when Phentermine is combined with Doxapram.
Doxazosin	The therapeutic efficacy of Doxazosin can be decreased when used in combination with Phentermine.
Doxepin	Phentermine may decrease the sedative and stimulatory activities of Doxepin.
Doxylamine	Phentermine may decrease the sedative and stimulatory activities of Doxylamine.
Dronabinol	The risk or severity of Tachycardia can be increased when Dronabinol is combined with Phentermine.
Dronedarone	The therapeutic efficacy of Dronedarone can be decreased when used in combination with Phentermine.
Droperidol	The therapeutic efficacy of Droperidol can be decreased when used in combination with Phentermine.
Droxidopa	The therapeutic efficacy of Phentermine can be increased when used in combination with Droxidopa.
Dulaglutide	The therapeutic efficacy of Dulaglutide can be increased when used in combination with Phentermine.
Duloxetine	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Duloxetine.
Dutasteride	The therapeutic efficacy of Dutasteride can be decreased when used in combination with Phentermine.
Dyphylline	The risk or severity of adverse effects can be increased when Phentermine is combined with Dyphylline.
Ebastine	Phentermine may decrease the sedative and stimulatory activities of Ebastine.
Eletriptan	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Eletriptan.
Eluxadoline	Phentermine may increase the analgesic activities of Eluxadoline.
Emedastine	Phentermine may decrease the sedative and stimulatory activities of Emedastine.
Empagliflozin	The therapeutic efficacy of Empagliflozin can be increased when used in combination with Phentermine.
Enalapril	Phentermine may decrease the antihypertensive activities of Enalapril.
Enalaprilat	Phentermine may decrease the antihypertensive activities of Enalaprilat.
Ephedrine	The therapeutic efficacy of Ephedrine can be increased when used in combination with Phentermine.
Epinastine	Phentermine may decrease the sedative and stimulatory activities of Epinastine.
Epinephrine	The therapeutic efficacy of Phentermine can be increased when used in combination with Epinephrine.
Eplerenone	Phentermine may decrease the antihypertensive activities of Eplerenone.
Epoprostenol	Phentermine may decrease the antihypertensive activities of Epoprostenol.
Eprosartan	Phentermine may decrease the antihypertensive activities of Eprosartan.
Eravacycline	The metabolism of Eravacycline can be decreased when combined with Phentermine.
Ergoloid mesylate	The therapeutic efficacy of Ergoloid mesylate can be decreased when used in combination with Phentermine.
Ergometrine	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Ergometrine.
Ergotamine	The therapeutic efficacy of Ergotamine can be decreased when used in combination with Phentermine.
Ertugliflozin	The therapeutic efficacy of Ertugliflozin can be increased when used in combination with Phentermine.
Escitalopram	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Escitalopram.
Esketamine	The risk or severity of hypertension can be increased when Esketamine is combined with Phentermine.
Esmolol	The therapeutic efficacy of Esmolol can be decreased when used in combination with Phentermine.
Etafedrine	The risk or severity of hypertension can be increased when Phentermine is combined with Etafedrine.
Ethanol	The risk or severity of cardiotoxicity can be increased when Ethanol is combined with Phentermine.
Ethosuximide	Phentermine can cause a decrease in the absorption of Ethosuximide resulting in a reduced serum concentration and potentially a decrease in efficacy.
Etilefrine	The risk or severity of adverse effects can be increased when Phentermine is combined with Etilefrine.
Etodolac	The risk or severity of hypertension can be increased when Phentermine is combined with Etodolac.
Etomidate	The risk or severity of hypertension can be increased when Phentermine is combined with Etomidate.
Etoricoxib	The risk or severity of hypertension can be increased when Phentermine is combined with Etoricoxib.
Exenatide	The therapeutic efficacy of Exenatide can be increased when used in combination with Phentermine.
Famotidine	Phentermine may decrease the sedative and stimulatory activities of Famotidine.
Felodipine	Phentermine may decrease the antihypertensive activities of Felodipine.
Fenbufen	The risk or severity of hypertension can be increased when Phentermine is combined with Fenbufen.
Fenfluramine	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Fenfluramine.
Fenoldopam	Phentermine may decrease the antihypertensive activities of Fenoldopam.
Fenoprofen	The risk or severity of hypertension can be increased when Phentermine is combined with Fenoprofen.
Fenoterol	The risk or severity of adverse effects can be increased when Phentermine is combined with Fenoterol.
Fentanyl	Phentermine may increase the analgesic activities of Fentanyl.
Ferrous ascorbate	The serum concentration of Phentermine can be decreased when it is combined with Ferrous ascorbate.
Fesoterodine	The risk or severity of Tachycardia can be increased when Phentermine is combined with Fesoterodine.
Fexofenadine	Phentermine may decrease the sedative and stimulatory activities of Fexofenadine.
Finasteride	The risk or severity of hypertension can be increased when Phentermine is combined with Finasteride.
Flavoxate	The risk or severity of Tachycardia can be increased when Phentermine is combined with Flavoxate.
Flibanserin	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Flibanserin.
Floctafenine	The risk or severity of hypertension can be increased when Phentermine is combined with Floctafenine.
Flunarizine	Phentermine may decrease the sedative and stimulatory activities of Flunarizine.
Fluoxetine	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Fluoxetine.
Flupentixol	The therapeutic efficacy of Flupentixol can be decreased when used in combination with Phentermine.
Fluphenazine	Fluphenazine may decrease the stimulatory activities of Phentermine.
Flurbiprofen	The risk or severity of hypertension can be increased when Phentermine is combined with Flurbiprofen.
Fluspirilene	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Fluspirilene.
Fluvoxamine	The risk or severity of serotonin syndrome can be increased when Fluvoxamine is combined with Phentermine.
Follitropin	The risk or severity of adverse effects can be increased when Phentermine is combined with Follitropin.
Formoterol	The risk or severity of hypertension can be increased when Phentermine is combined with Formoterol.
Fosinopril	Phentermine may decrease the antihypertensive activities of Fosinopril.
Fosphenytoin	The therapeutic efficacy of Fosphenytoin can be decreased when used in combination with Phentermine.
Frovatriptan	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Frovatriptan.
Furosemide	Phentermine may decrease the antihypertensive activities of Furosemide.
Gallamine triethiodide	The risk or severity of Tachycardia can be increased when Phentermine is combined with Gallamine triethiodide.
Gliclazide	The therapeutic efficacy of Gliclazide can be increased when used in combination with Phentermine.
Glimepiride	The therapeutic efficacy of Glimepiride can be increased when used in combination with Phentermine.
Glipizide	The therapeutic efficacy of Glipizide can be increased when used in combination with Phentermine.
Gliquidone	The therapeutic efficacy of Gliquidone can be increased when used in combination with Phentermine.
Glutamic acid	The serum concentration of Phentermine can be decreased when it is combined with Glutamic acid.
Glyburide	The therapeutic efficacy of Glyburide can be increased when used in combination with Phentermine.
Glycopyrronium	The risk or severity of Tachycardia can be increased when Phentermine is combined with Glycopyrronium.
Glymidine	The therapeutic efficacy of Glymidine can be increased when used in combination with Phentermine.
Granisetron	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Granisetron.
Guanabenz	Phentermine may decrease the antihypertensive activities of Guanabenz.
Guanadrel	The therapeutic efficacy of Guanadrel can be decreased when used in combination with Phentermine.
Guanethidine	The serum concentration of Guanethidine can be decreased when it is combined with Phentermine.
Guanfacine	Phentermine may decrease the antihypertensive activities of Guanfacine.
Guanoxan	Phentermine may decrease the antihypertensive activities of Guanoxan.
Haloperidol	The therapeutic efficacy of Phentermine can be decreased when used in combination with Haloperidol.
Halothane	The risk or severity of hypertension can be increased when Phentermine is combined with Halothane.
Hexocyclium	The risk or severity of Tachycardia can be increased when Phentermine is combined with Hexocyclium.
Homatropine methylbromide	The risk or severity of Tachycardia can be increased when Phentermine is combined with Homatropine methylbromide.
Hydralazine	Phentermine may decrease the antihypertensive activities of Hydralazine.
Hydrochlorothiazide	Phentermine may decrease the antihypertensive activities of Hydrochlorothiazide.
Hydrocodone	The risk or severity of serotonin syndrome can be increased when Hydrocodone is combined with Phentermine.
Hydroflumethiazide	Phentermine may decrease the antihypertensive activities of Hydroflumethiazide.
Hydromorphone	Phentermine may increase the analgesic activities of Hydromorphone.
Hydrotalcite	The serum concentration of Phentermine can be increased when it is combined with Hydrotalcite.
Hydroxyzine	Phentermine may decrease the sedative and stimulatory activities of Hydroxyzine.
Hyoscyamine	The risk or severity of Tachycardia can be increased when Phentermine is combined with Hyoscyamine.
Ibuprofen	The risk or severity of hypertension can be increased when Phentermine is combined with Ibuprofen.
Icosapent	The risk or severity of hypertension can be increased when Icosapent is combined with Phentermine.
Iloperidone	Phentermine may decrease the sedative and stimulatory activities of Iloperidone.
Imipramine	Phentermine may decrease the sedative and stimulatory activities of Imipramine.
Indacaterol	The risk or severity of hypertension can be increased when Phentermine is combined with Indacaterol.
Indapamide	Phentermine may decrease the antihypertensive activities of Indapamide.
Indomethacin	The risk or severity of hypertension can be increased when Phentermine is combined with Indomethacin.
Indoramin	The therapeutic efficacy of Indoramin can be decreased when used in combination with Phentermine.
Insulin aspart	The therapeutic efficacy of Insulin aspart can be increased when used in combination with Phentermine.
Insulin beef	The therapeutic efficacy of Insulin beef can be increased when used in combination with Phentermine.
Insulin degludec	The therapeutic efficacy of Insulin degludec can be increased when used in combination with Phentermine.
Insulin detemir	The therapeutic efficacy of Insulin detemir can be increased when used in combination with Phentermine.
Insulin glargine	The therapeutic efficacy of Insulin glargine can be increased when used in combination with Phentermine.
Insulin glulisine	The therapeutic efficacy of Insulin glulisine can be increased when used in combination with Phentermine.
Insulin human	The therapeutic efficacy of Insulin human can be increased when used in combination with Phentermine.
Insulin lispro	The therapeutic efficacy of Insulin lispro can be increased when used in combination with Phentermine.
Insulin pork	The therapeutic efficacy of Insulin pork can be increased when used in combination with Phentermine.
Iobenguane	Phentermine can cause a decrease in the absorption of Iobenguane resulting in a reduced serum concentration and potentially a decrease in efficacy.
Iofetamine I-123	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Iofetamine I-123.
Ioflupane I-123	Phentermine may decrease effectiveness of Ioflupane I-123 as a diagnostic agent.
Ipratropium	The risk or severity of Tachycardia can be increased when Phentermine is combined with Ipratropium.
Irbesartan	Phentermine may decrease the antihypertensive activities of Irbesartan.
Isocarboxazid	Isocarboxazid may increase the hypertensive activities of Phentermine.
Isoetharine	The risk or severity of hypertension can be increased when Phentermine is combined with Isoetharine.
Isoflurane	The risk or severity of hypertension can be increased when Phentermine is combined with Isoflurane.
Isometheptene	The risk or severity of hypertension can be increased when Phentermine is combined with Isometheptene.
Isoniazid	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Isoniazid.
Isoprenaline	The risk or severity of adverse effects can be increased when Phentermine is combined with Isoprenaline.
Isopropamide	The risk or severity of Tachycardia can be increased when Phentermine is combined with Isopropamide.
Isoxicam	The risk or severity of hypertension can be increased when Phentermine is combined with Isoxicam.
Isoxsuprine	The risk or severity of adverse effects can be increased when Phentermine is combined with Isoxsuprine.
Isradipine	Phentermine may decrease the antihypertensive activities of Isradipine.
Ketamine	The risk or severity of Tachycardia can be increased when Phentermine is combined with Ketamine.
Ketoprofen	The risk or severity of hypertension can be increased when Phentermine is combined with Ketoprofen.
Ketorolac	The risk or severity of hypertension can be increased when Phentermine is combined with Ketorolac.
Ketotifen	Phentermine may decrease the sedative and stimulatory activities of Ketotifen.
Labetalol	The therapeutic efficacy of Labetalol can be decreased when used in combination with Phentermine.
Lacidipine	Phentermine may decrease the antihypertensive activities of Lacidipine.
Lamotrigine	The therapeutic efficacy of Lamotrigine can be decreased when used in combination with Phentermine.
Lasmiditan	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Lasmiditan.
Lercanidipine	Phentermine may decrease the antihypertensive activities of Lercanidipine.
Levacetylmethadol	Phentermine may increase the analgesic activities of Levacetylmethadol.
Levamlodipine	Phentermine may decrease the antihypertensive activities of Levamlodipine.
Levobetaxolol	The therapeutic efficacy of Levobetaxolol can be decreased when used in combination with Phentermine.
Levocetirizine	Phentermine may decrease the sedative and stimulatory activities of Levocetirizine.
Levodopa	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Levodopa.
Levomilnacipran	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Levomilnacipran.
Levonordefrin	The therapeutic efficacy of Phentermine can be increased when used in combination with Levonordefrin.
Levorphanol	Phentermine may increase the analgesic activities of Levorphanol.
Levosalbutamol	The risk or severity of hypertension can be increased when Phentermine is combined with Levosalbutamol.
Levothyroxine	The risk or severity of adverse effects can be increased when Phentermine is combined with Levothyroxine.
Linagliptin	The therapeutic efficacy of Linagliptin can be increased when used in combination with Phentermine.
Linezolid	The risk or severity of hypertension can be increased when Linezolid is combined with Phentermine.
Liothyronine	The risk or severity of adverse effects can be increased when Phentermine is combined with Liothyronine.
Liotrix	The risk or severity of adverse effects can be increased when Phentermine is combined with Liotrix.
Liraglutide	The therapeutic efficacy of Liraglutide can be increased when used in combination with Phentermine.
Lisdexamfetamine	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Lisdexamfetamine.
Lisinopril	Phentermine may decrease the antihypertensive activities of Lisinopril.
Lisuride	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Lisuride.
Lithium carbonate	The therapeutic efficacy of Phentermine can be decreased when used in combination with Lithium carbonate.
Lithium citrate	The therapeutic efficacy of Phentermine can be decreased when used in combination with Lithium citrate.
Lithium hydroxide	The therapeutic efficacy of Phentermine can be decreased when used in combination with Lithium hydroxide.
Lixisenatide	The therapeutic efficacy of Lixisenatide can be increased when used in combination with Phentermine.
Lofexidine	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Lofexidine.
Loratadine	Phentermine may decrease the sedative and stimulatory activities of Loratadine.
Lorcaserin	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Lorcaserin.
Lornoxicam	The risk or severity of hypertension can be increased when Phentermine is combined with Lornoxicam.
Losartan	Phentermine may decrease the antihypertensive activities of Losartan.
Loxapine	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Loxapine.
Loxoprofen	The risk or severity of hypertension can be increased when Phentermine is combined with Loxoprofen.
Lumateperone	Lumateperone may decrease the stimulatory activities of Phentermine.
Lumiracoxib	The risk or severity of hypertension can be increased when Phentermine is combined with Lumiracoxib.
Lurasidone	The therapeutic efficacy of Lurasidone can be decreased when used in combination with Phentermine.
Macitentan	Phentermine may decrease the antihypertensive activities of Macitentan.
Magaldrate	The serum concentration of Phentermine can be increased when it is combined with Magaldrate.
Magnesium ascorbate	The serum concentration of Phentermine can be decreased when it is combined with Magnesium ascorbate.
Magnesium carbonate	The serum concentration of Phentermine can be increased when it is combined with Magnesium carbonate.
Magnesium hydroxide	The serum concentration of Phentermine can be increased when it is combined with Magnesium hydroxide.
Magnesium oxide	The serum concentration of Phentermine can be increased when it is combined with Magnesium oxide.
Magnesium silicate	The serum concentration of Phentermine can be increased when it is combined with Magnesium silicate.
Magnesium trisilicate	The serum concentration of Phentermine can be increased when it is combined with Magnesium trisilicate.
Manidipine	Phentermine may decrease the antihypertensive activities of Manidipine.
Maprotiline	Phentermine may decrease the sedative and stimulatory activities of Maprotiline.
Mazindol	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Mazindol.
Mebeverine	The risk or severity of Tachycardia can be increased when Phentermine is combined with Mebeverine.
Mecamylamine	Phentermine may decrease the antihypertensive activities of Mecamylamine.
Mecasermin	The therapeutic efficacy of Mecasermin can be increased when used in combination with Phentermine.
Meclizine	Phentermine may decrease the sedative and stimulatory activities of Meclizine.
Meclofenamic acid	The risk or severity of hypertension can be increased when Phentermine is combined with Meclofenamic acid.
Mefenamic acid	The risk or severity of hypertension can be increased when Phentermine is combined with Mefenamic acid.
Meloxicam	The risk or severity of hypertension can be increased when Phentermine is combined with Meloxicam.
Mepenzolate	The risk or severity of Tachycardia can be increased when Phentermine is combined with Mepenzolate.
Meperidine	The therapeutic efficacy of Meperidine can be increased when used in combination with Phentermine.
Mephentermine	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Mephentermine.
Mepyramine	Phentermine may decrease the sedative and stimulatory activities of Mepyramine.
Mercaptopurine	The risk or severity of adverse effects can be increased when Phentermine is combined with Mercaptopurine.
Mesalazine	The risk or severity of hypertension can be increased when Phentermine is combined with Mesalazine.
Mesoridazine	Mesoridazine may decrease the stimulatory activities of Phentermine.
Metamfetamine	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Metamfetamine.
Metamizole	The risk or severity of hypertension can be increased when Phentermine is combined with Metamizole.
Metaraminol	The risk or severity of adverse effects can be increased when Phentermine is combined with Metaraminol.
Metaxalone	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Metaxalone.
Metergoline	The risk or severity of hypertension can be increased when Phentermine is combined with Metergoline.
Metformin	The therapeutic efficacy of Metformin can be increased when used in combination with Phentermine.
Methadone	Phentermine may increase the analgesic activities of Methadone.
Methantheline	Phentermine may decrease the sedative and stimulatory activities of Methantheline.
Methazolamide	Methazolamide may decrease the excretion rate of Phentermine which could result in a higher serum level.
Methdilazine	Phentermine may decrease the sedative and stimulatory activities of Methdilazine.
Methenamine	The serum concentration of Phentermine can be decreased when it is combined with Methenamine.
Methimazole	The risk or severity of adverse effects can be increased when Phentermine is combined with Methimazole.
Methotrimeprazine	Phentermine may decrease the sedative and stimulatory activities of Methotrimeprazine.
Methoxamine	The risk or severity of adverse effects can be increased when Phentermine is combined with Methoxamine.
Methoxyflurane	The risk or severity of hypertension can be increased when Phentermine is combined with Methoxyflurane.
Methoxyphenamine	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Methoxyphenamine.
Methscopolamine	The risk or severity of Tachycardia can be increased when Phentermine is combined with Methscopolamine.
Methscopolamine bromide	The risk or severity of Tachycardia can be increased when Phentermine is combined with Methscopolamine bromide.
Methyldopa	Phentermine may decrease the antihypertensive activities of Methyldopa.
Methylene blue	Phentermine may increase the serotonergic activities of Methylene blue.
Methylergometrine	The risk or severity of hypertension can be increased when Phentermine is combined with Methylergometrine.
Methylphenidate	The risk or severity of hypertension can be increased when Phentermine is combined with Methylphenidate.
Methylphenobarbital	The serum concentration of Methylphenobarbital can be decreased when it is combined with Phentermine.
Methysergide	The risk or severity of hypertension can be increased when Phentermine is combined with Methysergide.
Metixene	The risk or severity of Tachycardia can be increased when Phentermine is combined with Metixene.
Metoclopramide	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Metoclopramide.
Metocurine	The risk or severity of Tachycardia can be increased when Phentermine is combined with Metocurine.
Metolazone	Phentermine may decrease the antihypertensive activities of Metolazone.
Metoprolol	The therapeutic efficacy of Metoprolol can be decreased when used in combination with Phentermine.
Metreleptin	The metabolism of Phentermine can be increased when combined with Metreleptin.
Metyrosine	Phentermine may decrease the antihypertensive activities of Metyrosine.
Mianserin	Phentermine may decrease the sedative and stimulatory activities of Mianserin.
Midodrine	The risk or severity of adverse effects can be increased when Phentermine is combined with Midodrine.
Mifepristone	The therapeutic efficacy of Mifepristone can be increased when used in combination with Phentermine.
Miglitol	The therapeutic efficacy of Miglitol can be increased when used in combination with Phentermine.
Milnacipran	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Milnacipran.
Minaprine	Minaprine may increase the hypertensive activities of Phentermine.
Minoxidil	Phentermine may decrease the antihypertensive activities of Minoxidil.
Mirabegron	The risk or severity of hypertension can be increased when Phentermine is combined with Mirabegron.
Mirtazapine	Phentermine may increase the serotonergic activities of Mirtazapine.
Mivacurium	The risk or severity of Tachycardia can be increased when Phentermine is combined with Mivacurium.
Mizolastine	Phentermine may decrease the sedative and stimulatory activities of Mizolastine.
Moclobemide	Moclobemide may increase the hypertensive activities of Phentermine.
Modafinil	The risk or severity of hypertension can be increased when Phentermine is combined with Modafinil.
Moexipril	Phentermine may decrease the antihypertensive activities of Moexipril.
Molindone	Molindone may decrease the stimulatory activities of Phentermine.
Moricizine	Moricizine may decrease the stimulatory activities of Phentermine.
Morphine	Phentermine may increase the analgesic activities of Morphine.
Moxisylyte	The therapeutic efficacy of Moxisylyte can be decreased when used in combination with Phentermine.
Moxonidine	The risk or severity of hypertension can be increased when Phentermine is combined with Moxonidine.
Muzolimine	Phentermine may decrease the antihypertensive activities of Muzolimine.
Nabilone	The risk or severity of Tachycardia can be increased when Nabilone is combined with Phentermine.
Nabumetone	The risk or severity of hypertension can be increased when Phentermine is combined with Nabumetone.
Nadolol	The therapeutic efficacy of Nadolol can be decreased when used in combination with Phentermine.
Nalbuphine	Phentermine may increase the analgesic activities of Nalbuphine.
Naloxegol	Phentermine may increase the analgesic activities of Naloxegol.
Naltrexone	Phentermine may increase the analgesic activities of Naltrexone.
Naphazoline	The risk or severity of hypertension can be increased when Phentermine is combined with Naphazoline.
Naproxen	The risk or severity of hypertension can be increased when Phentermine is combined with Naproxen.
Naratriptan	The metabolism of Naratriptan can be decreased when combined with Phentermine.
Nateglinide	The therapeutic efficacy of Nateglinide can be increased when used in combination with Phentermine.
Naxitamab	The risk or severity of hypertension can be increased when Phentermine is combined with Naxitamab.
Nebivolol	The therapeutic efficacy of Nebivolol can be decreased when used in combination with Phentermine.
Nefazodone	The therapeutic efficacy of Nefazodone can be decreased when used in combination with Phentermine.
Niacinamide ascorbate	The serum concentration of Phentermine can be decreased when it is combined with Niacinamide ascorbate.
Nialamide	Nialamide may increase the hypertensive activities of Phentermine.
Nicardipine	The therapeutic efficacy of Nicardipine can be decreased when used in combination with Phentermine.
Nicergoline	The therapeutic efficacy of Nicergoline can be decreased when used in combination with Phentermine.
Nicorandil	Phentermine may decrease the antihypertensive activities of Nicorandil.
Nicotine	The risk or severity of Tachycardia can be increased when Nicotine is combined with Phentermine.
Nilvadipine	Phentermine may decrease the antihypertensive activities of Nilvadipine.
Nimesulide	The risk or severity of hypertension can be increased when Phentermine is combined with Nimesulide.
Nimodipine	Phentermine may decrease the antihypertensive activities of Nimodipine.
Nisoldipine	Phentermine may decrease the antihypertensive activities of Nisoldipine.
Nitrendipine	Phentermine may decrease the antihypertensive activities of Nitrendipine.
Nitroglycerin	Phentermine may decrease the antihypertensive activities of Nitroglycerin.
Nitroprusside	Phentermine may decrease the antihypertensive activities of Nitroprusside.
Nitrous oxide	The risk or severity of hypertension can be increased when Phentermine is combined with Nitrous oxide.
Nizatidine	Phentermine may decrease the sedative and stimulatory activities of Nizatidine.
Norepinephrine	The therapeutic efficacy of Phentermine can be increased when used in combination with Norepinephrine.
Normethadone	Phentermine may increase the analgesic activities of Normethadone.
Nortriptyline	Phentermine may decrease the sedative and stimulatory activities of Nortriptyline.
Nylidrin	The risk or severity of adverse effects can be increased when Phentermine is combined with Nylidrin.
Olanzapine	Phentermine may decrease the sedative and stimulatory activities of Olanzapine.
Oliceridine	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Oliceridine.
Olmesartan	Phentermine may decrease the antihypertensive activities of Olmesartan.
Olodaterol	The risk or severity of hypertension can be increased when Phentermine is combined with Olodaterol.
Olsalazine	The risk or severity of hypertension can be increased when Phentermine is combined with Olsalazine.
Ondansetron	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Ondansetron.
Opium	Phentermine may increase the analgesic activities of Opium.
Orciprenaline	The risk or severity of adverse effects can be increased when Phentermine is combined with Orciprenaline.
Orphenadrine	Phentermine may decrease the sedative and stimulatory activities of Orphenadrine.
Oxaprozin	The risk or severity of hypertension can be increased when Phentermine is combined with Oxaprozin.
Oxatomide	Phentermine may decrease the sedative and stimulatory activities of Oxatomide.
Oxprenolol	The therapeutic efficacy of Oxprenolol can be decreased when used in combination with Phentermine.
Oxtriphylline	The risk or severity of adverse effects can be increased when Phentermine is combined with Oxtriphylline.
Oxybutynin	The risk or severity of Tachycardia can be increased when Phentermine is combined with Oxybutynin.
Oxycodone	Phentermine may increase the analgesic activities of Oxycodone.
Oxymetazoline	The risk or severity of adverse effects can be increased when Phentermine is combined with Oxymetazoline.
Oxymorphone	Phentermine may increase the analgesic activities of Oxymorphone.
Oxyphenbutazone	The risk or severity of hypertension can be increased when Phentermine is combined with Oxyphenbutazone.
Oxyphencyclimine	The risk or severity of Tachycardia can be increased when Phentermine is combined with Oxyphencyclimine.
Oxyphenonium	The risk or severity of Tachycardia can be increased when Phentermine is combined with Oxyphenonium.
Paliperidone	The therapeutic efficacy of Paliperidone can be decreased when used in combination with Phentermine.
Palonosetron	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Palonosetron.
Pancuronium	The risk or severity of Tachycardia can be increased when Phentermine is combined with Pancuronium.
Parathyroid hormone	The risk or severity of adverse effects can be increased when Phentermine is combined with Parathyroid hormone.
Parecoxib	The risk or severity of hypertension can be increased when Phentermine is combined with Parecoxib.
Pargyline	Pargyline may increase the hypertensive activities of Phentermine.
Paroxetine	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Paroxetine.
Penbutolol	The therapeutic efficacy of Penbutolol can be decreased when used in combination with Phentermine.
Pentamidine	The therapeutic efficacy of Pentamidine can be increased when used in combination with Phentermine.
Pentazocine	Phentermine may increase the analgesic activities of Pentazocine.
Pentolinium	Phentermine may decrease the antihypertensive activities of Pentolinium.
Pentoxifylline	The risk or severity of adverse effects can be increased when Phentermine is combined with Pentoxifylline.
Perazine	Perazine may decrease the stimulatory activities of Phentermine.
Pergolide	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Pergolide.
Periciazine	The therapeutic efficacy of Periciazine can be decreased when used in combination with Phentermine.
Perindopril	Phentermine may decrease the antihypertensive activities of Perindopril.
Perphenazine	Perphenazine may decrease the stimulatory activities of Phentermine.
Phendimetrazine	The risk or severity of hypertension can be increased when Phentermine is combined with Phendimetrazine.
Phenelzine	Phenelzine may increase the hypertensive activities of Phentermine.
Phenformin	The therapeutic efficacy of Phenformin can be increased when used in combination with Phentermine.
Phenindamine	Phentermine may decrease the sedative and stimulatory activities of Phenindamine.
Pheniramine	Phentermine may decrease the sedative and stimulatory activities of Pheniramine.
Phenmetrazine	The risk or severity of adverse effects can be increased when Phentermine is combined with Phenmetrazine.
Phenobarbital	The serum concentration of Phenobarbital can be decreased when it is combined with Phentermine.
Phenoxybenzamine	The therapeutic efficacy of Phenoxybenzamine can be decreased when used in combination with Phentermine.
Phentolamine	The therapeutic efficacy of Phentolamine can be decreased when used in combination with Phentermine.
Phenylbutazone	The risk or severity of hypertension can be increased when Phentermine is combined with Phenylbutazone.
Phenylephrine	The metabolism of Phenylephrine can be decreased when combined with Phentermine.
Phenylpropanolamine	The risk or severity of adverse effects can be increased when Phentermine is combined with Phenylpropanolamine.
Phenytoin	The therapeutic efficacy of Phenytoin can be decreased when used in combination with Phentermine.
Pimozide	The therapeutic efficacy of Phentermine can be decreased when used in combination with Pimozide.
Pinacidil	Phentermine may decrease the antihypertensive activities of Pinacidil.
Pindolol	The therapeutic efficacy of Pindolol can be decreased when used in combination with Phentermine.
Pioglitazone	The therapeutic efficacy of Pioglitazone can be increased when used in combination with Phentermine.
Pipecuronium	The risk or severity of Tachycardia can be increased when Phentermine is combined with Pipecuronium.
Pipotiazine	Pipotiazine may decrease the stimulatory activities of Phentermine.
Pirbuterol	The risk or severity of hypertension can be increased when Phentermine is combined with Pirbuterol.
Pirenzepine	The risk or severity of Tachycardia can be increased when Phentermine is combined with Pirenzepine.
Piritramide	Phentermine may increase the analgesic activities of Piritramide.
Piroxicam	The risk or severity of hypertension can be increased when Phentermine is combined with Piroxicam.
Pitolisant	The serum concentration of Phentermine can be decreased when it is combined with Pitolisant.
Pizotifen	Phentermine may decrease the sedative and stimulatory activities of Pizotifen.
Polythiazide	Phentermine may decrease the antihypertensive activities of Polythiazide.
Potassium citrate	The excretion of Phentermine can be decreased when combined with Potassium citrate.
Potassium Iodide	The risk or severity of adverse effects can be increased when Phentermine is combined with Potassium Iodide.
Potassium perchlorate	The risk or severity of adverse effects can be increased when Phentermine is combined with Potassium perchlorate.
Practolol	The therapeutic efficacy of Practolol can be decreased when used in combination with Phentermine.
Pramlintide	The therapeutic efficacy of Pramlintide can be increased when used in combination with Phentermine.
Prazosin	The therapeutic efficacy of Prazosin can be decreased when used in combination with Phentermine.
Primidone	The serum concentration of Primidone can be decreased when it is combined with Phentermine.
Procaine	Procaine may increase the hypertensive activities of Phentermine.
Procarbazine	Procarbazine may increase the hypertensive activities of Phentermine.
Procaterol	The risk or severity of adverse effects can be increased when Phentermine is combined with Procaterol.
Prochlorperazine	Prochlorperazine may decrease the stimulatory activities of Phentermine.
Procyclidine	The risk or severity of Tachycardia can be increased when Phentermine is combined with Procyclidine.
Profenamine	The therapeutic efficacy of Profenamine can be decreased when used in combination with Phentermine.
Promazine	Phentermine may decrease the sedative and stimulatory activities of Promazine.
Promethazine	Phentermine may decrease the sedative and stimulatory activities of Promethazine.
Propafenone	The therapeutic efficacy of Propafenone can be decreased when used in combination with Phentermine.
Propantheline	The risk or severity of Tachycardia can be increased when Phentermine is combined with Propantheline.
Propiomazine	Phentermine may decrease the sedative and stimulatory activities of Propiomazine.
Propiverine	The therapeutic efficacy of Propiverine can be decreased when used in combination with Phentermine.
Propofol	The risk or severity of hypertension can be increased when Phentermine is combined with Propofol.
Propranolol	The therapeutic efficacy of Propranolol can be decreased when used in combination with Phentermine.
Propylthiouracil	The risk or severity of adverse effects can be increased when Phentermine is combined with Propylthiouracil.
Protirelin	The risk or severity of adverse effects can be increased when Phentermine is combined with Protirelin.
Protokylol	The therapeutic efficacy of Phentermine can be increased when used in combination with Protokylol.
Protriptyline	The therapeutic efficacy of Protriptyline can be increased when used in combination with Phentermine.
Pseudoephedrine	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Pseudoephedrine.
Quetiapine	Phentermine may decrease the sedative and stimulatory activities of Quetiapine.
Quinapril	Phentermine may decrease the antihypertensive activities of Quinapril.
Quinidine	The therapeutic efficacy of Quinidine can be decreased when used in combination with Phentermine.
Quinine	The therapeutic efficacy of Quinine can be increased when used in combination with Phentermine.
Quinupramine	The therapeutic efficacy of Quinupramine can be increased when used in combination with Phentermine.
Racepinephrine	The therapeutic efficacy of Phentermine can be increased when used in combination with Racepinephrine.
Ramipril	Phentermine may decrease the antihypertensive activities of Ramipril.
Ranitidine	Phentermine may decrease the sedative and stimulatory activities of Ranitidine.
Rapacuronium	The risk or severity of Tachycardia can be increased when Phentermine is combined with Rapacuronium.
Rasagiline	Rasagiline may increase the hypertensive activities of Phentermine.
Remifentanil	Phentermine may increase the analgesic activities of Remifentanil.
Remoxipride	Remoxipride may decrease the stimulatory activities of Phentermine.
Repaglinide	The therapeutic efficacy of Repaglinide can be increased when used in combination with Phentermine.
Rescinnamine	The risk or severity of hypertension can be increased when Phentermine is combined with Rescinnamine.
Reserpine	The serum concentration of Phentermine can be decreased when it is combined with Reserpine.
Rilmenidine	The risk or severity of hypertension can be increased when Phentermine is combined with Rilmenidine.
Rimonabant	The risk or severity of Tachycardia can be increased when Rimonabant is combined with Phentermine.
Riociguat	Phentermine may decrease the antihypertensive activities of Riociguat.
Risperidone	Phentermine may decrease the sedative and stimulatory activities of Risperidone.
Ritodrine	The risk or severity of adverse effects can be increased when Phentermine is combined with Ritodrine.
Ritonavir	The serum concentration of Phentermine can be increased when it is combined with Ritonavir.
Rizatriptan	The metabolism of Rizatriptan can be decreased when combined with Phentermine.
Rocuronium	The risk or severity of Tachycardia can be increased when Phentermine is combined with Rocuronium.
Rofecoxib	The risk or severity of hypertension can be increased when Phentermine is combined with Rofecoxib.
Rosiglitazone	The therapeutic efficacy of Rosiglitazone can be increased when used in combination with Phentermine.
Rotigotine	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Rotigotine.
Rupatadine	Phentermine may decrease the sedative and stimulatory activities of Rupatadine.
Safinamide	Safinamide may increase the hypertensive activities of Phentermine.
Salbutamol	The risk or severity of hypertension can be increased when Phentermine is combined with Salbutamol.
Salicylamide	The risk or severity of hypertension can be increased when Phentermine is combined with Salicylamide.
Salicylic acid	The risk or severity of hypertension can be increased when Phentermine is combined with Salicylic acid.
Salmeterol	The risk or severity of hypertension can be increased when Phentermine is combined with Salmeterol.
Salmon calcitonin	The risk or severity of adverse effects can be increased when Phentermine is combined with Salmon calcitonin.
Salsalate	The risk or severity of hypertension can be increased when Phentermine is combined with Salsalate.
Satralizumab	The serum concentration of Phentermine can be decreased when it is combined with Satralizumab.
Saxagliptin	The therapeutic efficacy of Saxagliptin can be increased when used in combination with Phentermine.
Scopolamine	The risk or severity of Tachycardia can be increased when Phentermine is combined with Scopolamine.
Selegiline	The risk or severity of adverse effects can be increased when Selegiline is combined with Phentermine.
Selexipag	Phentermine may decrease the antihypertensive activities of Selexipag.
Selpercatinib	The risk or severity of hypertension can be increased when Phentermine is combined with Selpercatinib.
Semaglutide	The therapeutic efficacy of Semaglutide can be increased when used in combination with Phentermine.
Serdexmethylphenidate	The risk or severity of hypertension can be increased when Phentermine is combined with Serdexmethylphenidate.
Sertindole	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Sertindole.
Sertraline	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Sertraline.
Sevoflurane	The risk or severity of hypertension can be increased when Phentermine is combined with Sevoflurane.
Sibutramine	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Sibutramine.
Silodosin	The therapeutic efficacy of Silodosin can be decreased when used in combination with Phentermine.
Siponimod	The risk or severity of hypertension can be increased when Phentermine is combined with Siponimod.
Sitagliptin	The therapeutic efficacy of Sitagliptin can be increased when used in combination with Phentermine.
Sitaxentan	Phentermine may decrease the antihypertensive activities of Sitaxentan.
Sodium ascorbate	The serum concentration of Phentermine can be decreased when it is combined with Sodium ascorbate.
Sodium bicarbonate	The serum concentration of Phentermine can be increased when it is combined with Sodium bicarbonate.
Sodium citrate	The excretion of Phentermine can be decreased when combined with Sodium citrate.
Sodium phosphate, dibasic	The serum concentration of Phentermine can be decreased when it is combined with Sodium phosphate, dibasic.
Sodium phosphate, monobasic	The serum concentration of Phentermine can be decreased when it is combined with Sodium phosphate, monobasic.
Solifenacin	The risk or severity of hypertension can be increased when Phentermine is combined with Solifenacin.
Solriamfetol	The risk or severity of hypertension can be increased when Solriamfetol is combined with Phentermine.
Sotagliflozin	The therapeutic efficacy of Sotagliflozin can be increased when used in combination with Phentermine.
Sotalol	The therapeutic efficacy of Sotalol can be decreased when used in combination with Phentermine.
Sotorasib	The serum concentration of Phentermine can be decreased when it is combined with Sotorasib.
Spirapril	Phentermine may decrease the antihypertensive activities of Spirapril.
St. John’s Wort	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with St. John’s Wort.
Sufentanil	Phentermine may increase the analgesic activities of Sufentanil.
Sulfadiazine	The therapeutic efficacy of Sulfadiazine can be increased when used in combination with Phentermine.
Sulfamethoxazole	The therapeutic efficacy of Sulfamethoxazole can be increased when used in combination with Phentermine.
Sulfasalazine	The risk or severity of hypertension can be increased when Phentermine is combined with Sulfasalazine.
Sulfisoxazole	The therapeutic efficacy of Sulfisoxazole can be increased when used in combination with Phentermine.
Sulindac	The risk or severity of hypertension can be increased when Phentermine is combined with Sulindac.
Sulpiride	Sulpiride may decrease the stimulatory activities of Phentermine.
Sultopride	Sultopride may decrease the stimulatory activities of Phentermine.
Sumatriptan	The metabolism of Sumatriptan can be decreased when combined with Phentermine.
Sunitinib	The therapeutic efficacy of Sunitinib can be increased when used in combination with Phentermine.
Tadalafil	Phentermine may decrease the antihypertensive activities of Tadalafil.
Tamsulosin	The therapeutic efficacy of Tamsulosin can be decreased when used in combination with Phentermine.
Tapentadol	Phentermine may increase the analgesic activities of Tapentadol.
Tedizolid phosphate	Tedizolid phosphate may increase the hypertensive activities of Phentermine.
Tegaserod	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Tegaserod.
Telmisartan	Phentermine may decrease the antihypertensive activities of Telmisartan.
Tenoxicam	The risk or severity of hypertension can be increased when Phentermine is combined with Tenoxicam.
Terazosin	The therapeutic efficacy of Terazosin can be decreased when used in combination with Phentermine.
Terbutaline	The risk or severity of adverse effects can be increased when Phentermine is combined with Terbutaline.
Terfenadine	Phentermine may decrease the sedative and stimulatory activities of Terfenadine.
Teriparatide	The risk or severity of adverse effects can be increased when Phentermine is combined with Teriparatide.
Testosterone undecanoate	Testosterone undecanoate may increase the hypertensive activities of Phentermine.
Tetryzoline	The risk or severity of adverse effects can be increased when Phentermine is combined with Tetryzoline.
Theophylline	The risk or severity of adverse effects can be increased when Phentermine is combined with Theophylline.
Thiethylperazine	Thiethylperazine may decrease the stimulatory activities of Phentermine.
Thioridazine	The therapeutic efficacy of Thioridazine can be decreased when used in combination with Phentermine.
Thiothixene	Thiothixene may decrease the stimulatory activities of Phentermine.
Thonzylamine	Phentermine may decrease the sedative and stimulatory activities of Thonzylamine.
Thyroid, porcine	The risk or severity of adverse effects can be increased when Phentermine is combined with Thyroid, porcine.
Thyrotropin alfa	The risk or severity of adverse effects can be increased when Phentermine is combined with Thyrotropin alfa.
Tiaprofenic acid	The risk or severity of hypertension can be increased when Phentermine is combined with Tiaprofenic acid.
Timolol	The therapeutic efficacy of Timolol can be decreased when used in combination with Phentermine.
Tiotropium	The risk or severity of Tachycardia can be increased when Phentermine is combined with Tiotropium.
Tizanidine	The risk or severity of Tachycardia can be increased when Phentermine is combined with Tizanidine.
Tolazamide	The therapeutic efficacy of Tolazamide can be increased when used in combination with Phentermine.
Tolazoline	The therapeutic efficacy of Tolazoline can be decreased when used in combination with Phentermine.
Tolbutamide	The therapeutic efficacy of Tolbutamide can be increased when used in combination with Phentermine.
Tolfenamic acid	The risk or severity of hypertension can be increased when Phentermine is combined with Tolfenamic acid.
Tolmetin	The risk or severity of hypertension can be increased when Phentermine is combined with Tolmetin.
Tolterodine	The risk or severity of Tachycardia can be increased when Phentermine is combined with Tolterodine.
Torasemide	Phentermine may decrease the antihypertensive activities of Torasemide.
Tramadol	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Tramadol.
Trandolapril	Phentermine may decrease the antihypertensive activities of Trandolapril.
Tranylcypromine	Tranylcypromine may increase the hypertensive activities of Phentermine.
Trazodone	The risk or severity of serotonin syndrome can be increased when Trazodone is combined with Phentermine.
Treprostinil	Phentermine may decrease the antihypertensive activities of Treprostinil.
Trichlormethiazide	Phentermine may decrease the antihypertensive activities of Trichlormethiazide.
Trichloroethylene	The risk or severity of hypertension can be increased when Phentermine is combined with Trichloroethylene.
Trifluoperazine	The therapeutic efficacy of Trifluoperazine can be decreased when used in combination with Phentermine.
Triflupromazine	Triflupromazine may decrease the stimulatory activities of Phentermine.
Trihexyphenidyl	The risk or severity of Tachycardia can be increased when Phentermine is combined with Trihexyphenidyl.
Trimebutine	The risk or severity of Tachycardia can be increased when Phentermine is combined with Trimebutine.
Trimethaphan	Phentermine may decrease the antihypertensive activities of Trimethaphan.
Trimipramine	Phentermine may decrease the sedative and stimulatory activities of Trimipramine.
Tripelennamine	Phentermine may decrease the sedative and stimulatory activities of Tripelennamine.
Triprolidine	Phentermine may decrease the sedative and stimulatory activities of Triprolidine.
Tritoqualine	Phentermine may decrease the sedative and stimulatory activities of Tritoqualine.
Troglitazone	The therapeutic efficacy of Troglitazone can be increased when used in combination with Phentermine.
Trospium	The risk or severity of Tachycardia can be increased when Phentermine is combined with Trospium.
Tryptophan	The risk or severity of serotonin syndrome can be increased when Tryptophan is combined with Phentermine.
Tucatinib	The metabolism of Tucatinib can be decreased when combined with Phentermine.
Umeclidinium	The risk or severity of Tachycardia can be increased when Phentermine is combined with Umeclidinium.
Valdecoxib	The risk or severity of hypertension can be increased when Phentermine is combined with Valdecoxib.
Valproate bismuth	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Valproate bismuth.
Valproic acid	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Valproic acid.
Valsartan	Phentermine may decrease the antihypertensive activities of Valsartan.
Venlafaxine	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Venlafaxine.
Verapamil	The therapeutic efficacy of Verapamil can be decreased when used in combination with Phentermine.
Vilanterol	The risk or severity of hypertension can be increased when Phentermine is combined with Vilanterol.
Vilazodone	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Vilazodone.
Vildagliptin	The therapeutic efficacy of Vildagliptin can be increased when used in combination with Phentermine.
Vortioxetine	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Vortioxetine.
Xamoterol	The risk or severity of hypertension can be increased when Phentermine is combined with Xamoterol.
Xylometazoline	The risk or severity of hypertension can be increased when Phentermine is combined with Xylometazoline.
Yohimbine	The therapeutic efficacy of Yohimbine can be decreased when used in combination with Phentermine.
Zimelidine	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Zimelidine.
Zinc ascorbate	The serum concentration of Phentermine can be decreased when it is combined with Zinc ascorbate.
Ziprasidone	Phentermine may decrease the sedative and stimulatory activities of Ziprasidone.
Zofenopril	Phentermine may decrease the antihypertensive activities of Zofenopril.
Zolmitriptan	The metabolism of Zolmitriptan can be decreased when combined with Phentermine.
Zonisamide	Zonisamide may decrease the excretion rate of Phentermine which could result in a higher serum level.
Zotepine	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Zotepine.
Zuclopenthixol	Phentermine may decrease the sedative and stimulatory activities of Zuclopenthixol.

Nutraceuticals / Supplements

Drug	Interaction
Ascorbic acid	The serum concentration of Phentermine can be decreased when it is combined with Ascorbic acid.
Calcium ascorbate	The serum concentration of Phentermine can be decreased when it is combined with Calcium ascorbate.
Citric acid	The excretion of Phentermine can be decreased when combined with Citric acid.
Ephedra sinica root	The risk or severity of hypertension can be increased when Phentermine is combined with Ephedra sinica root.
Glutamic acid	The serum concentration of Phentermine can be decreased when it is combined with Glutamic acid.
Icosapent	The risk or severity of hypertension can be increased when Icosapent is combined with Phentermine.
Magnesium ascorbate	The serum concentration of Phentermine can be decreased when it is combined with Magnesium ascorbate.
Niacinamide ascorbate	The serum concentration of Phentermine can be decreased when it is combined with Niacinamide ascorbate.
Palmidrol	The risk or severity of Tachycardia can be increased when Palmidrol is combined with Phentermine.
Serotonin	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with Serotonin.
Sodium ascorbate	The serum concentration of Phentermine can be decreased when it is combined with Sodium ascorbate.
St. John’s Wort	The risk or severity of serotonin syndrome can be increased when Phentermine is combined with St. John’s Wort.
Tryptophan	The risk or severity of serotonin syndrome can be increased when Tryptophan is combined with Phentermine.
Tyramine	The risk or severity of adverse effects can be increased when Phentermine is combined with Tyramine.
Zinc ascorbate	The serum concentration of Phentermine can be decreased when it is combined with Zinc ascorbate

Drug-drug interactions are extracted from drug labels and scientific publications. Data supplied by DrugBank

Phentermine Interactions

Drugs, Nutraceuticals and SupplementsShown To Interact Negatively with Phentermine

Drugs, Nutraceuticals and Supplements
Shown To Interact Negatively with Phentermine