Can you drink coffee while on Phentermine?

by Rakib Sarwar, RPh on December 12, 2024
Last updated on December 12, 2024

Dreaming of shedding extra pounds, getting those muscles in shape, and bursting with energy, but turning your back on cooking and working out? Then, wave those weight loss wishes farewell.

a cup of coffee

Do you think that a tiny pill can magically remove all the accumulated fat? Nutritionists, medical doctors, as well as common people have understood that the key to fitness is a balanced diet, healthy lifestyle, and regular exercising.

However, if you are already overweight, you can trigger fat melting mechanisms, and reinforce your healthy lifestyle with special medications designed for improving your weight loss. One of the most popular ones is Phentermine.

We’re sure you will recognize yourself in the following scenario: you are overweight and you decided to change your life. You will exercise, start a balanced diet, and count your calories.

Additionally, your doctor prescribed Phentermine, but you want to reinforce its effects with some of the natural weight loss supplements, such as caffeine. However, you’re not sure whether consuming Phentermine and coffee together is a good idea or not.

In this article, we will answer if you can drink coffee while on Phentermine. Furthermore, we will talk about whether this combination leads to an increased and faster weight loss or has some hidden risks and side effects for your health.

Let’s first introduce Phentermine for all of you who might not know enough about this powerful weight loss medication.

The effects of Phentermine on weight loss

Phentermine is a prescription medication commonly used to promote weight loss by reducing the feeling of hunger, i.e., increasing satiety (1). This medicine can be used only upon doctor’s prescription. Furthermore, you must always stick to the given schedule and length of the treatment period. Taking more than prescribed can cause dangerous side effects. Let’s learn more about the nature of Phentermine.

Phentermine is a stimulant, which means that this medicine increases the number of heartbeats, i.e., heart rate. It also increases blood pressure. The drug acts on the central nervous system like many other stimulants (2), including caffeine. This is why the combination of Phentermine and coffee is fascinating and has been tested by scientists. We will talk about this issue a little bit later in the article. Let’s get back to Phentermine.

Phentermine was approved in 1959 by the FDA. It became more popular in the following decades. Its popularity continues to grow even today because of its amazing results in the reduction of fat deposits. The key mechanism of this medication is influencing the central nervous system and the hypothalamus and thus keeping the hunger under control (3).

As Phentermine is a slimming product, numerous studies were conducted with the aim of determining its composition. It was found that it includes sodium nitride, phenylpropanolamine, caffeine and 3,5-diiodothyronine (3). These chemicals affect the central nervous system and can cause addiction. At the same time, these products can have some serious side effects other than those affecting the central nervous system if used with some substances, such as caffeine. We will mention those side effects later.

Phentermine is usually used in obese individuals with severe weight problems. It has the potential to become addictive because its structure resembles amphetamines.

Phentermine is a substance that leads to increased metabolism, increased glucose utilization, higher lipolysis, and fat usage as an energy source. Above all this, phentermine diminishes a feeling of hunger and creates a sense of satiety.

However, the fact is that phentermine has the same side effects as all amphetamines – severe sleep disorders, nausea, vomiting, diarrhea, intermittent breath, etc. This is why Phentermine must be used under medical supervision. Do not take phentermine unless you have a prescription from your doctor (4).

The effects of caffeine on weight loss

People often consume coffee as a relaxing drink they enjoy. Some people see it as an elixir but in a certain way, it can become a real obsession. Also, caffeine can cause addiction.

However, it has numerous positive effects on weight loss. It accelerates your metabolism and helps burn the accumulated fat (5). Caffeine also stimulates your central nervous system and provides extra energy and motivation for exercising (6). Caffeine stimulates the release of fat from the fatty cells and involves them in the creation of energy.

As scientists have found that there are similarities in the way in which caffeine and Phentermine work, a reasonable doubt that drinking coffee while on Phentermine might cause some side effects. Let’s see how Phentermine and coffee act when used together.

Why avoid coffee while on Phentermine?

Even though both caffeine and Phentermine usually do trigger your weight loss, there are certain side effects of both caffeine and Phentermine consumption that can endanger your health. If that is the case, it’s time for you to consider changing your habits.

While a small amount of coffee can improve your memory and neurological health (6), and Phentermine pills are very effective in the short run, consuming your favorite caffeine boost drink while on Phentermine can disrupt your body functions. Do you think you’ve reached that limit? If you are not sure, consider visiting your medical care provider if you notice any of the following:

  • Irregular heartbeat: Caffeine is a stimulant that acts on the central nervous system and can accelerate your heartbeat. Similarly, Phentermine is a stimulant that accelerates your metabolism, as well as your heartbeat rate. Consuming both Phentermine and coffee can lead to an irregular and accelerated heartbeat. That is a condition you definitely want to avoid.
  • Nervousness and tremor: trembling, restlessness, nervousness – these symptoms look like logical Phentermine and coffee consequences. Caffeine can activate or release some of the hormones such as adrenaline, which prevents fatigue in humans, but can also cause nervousness. Phentermine acts similarly, as it is a strong nervous system stimulant. Combination of the two can double this effect, resulting in tremor and anxiety.
  • Increase in your blood pressure: It’s already well-known that caffeine, i.e., coffee consumption can increase your blood pressure. This is why people with low blood pressure often use coffee as a natural remedy for their condition. On the other hand, people with high blood pressure usually avoid coffee, as it can worsen their situation. Phentermine also increases blood pressure. This is why consuming Phentermine and coffee at the same time is not recommended.
  • Too many visits to the toilet: Caffeine acts as a mild diuretic and can induce certain people to more frequent urination. This can be more embarrassing than dangerous, but it can also mean that the nutrients are not absorbed as they should be, because the fluids flow too fast through our body. Phentermine has the same effect, as it accelerates the metabolism. This side effect is not limited only to frequent urination. Some people may experience frequent defecation too. Boost in metabolism as a consequence of coffee and Phentermine intake is usually doubled, for most of the people. This is why simultaneous consumption of both Phentermine and coffee can lead to lots of visits to the restroom in a day.
  • Stomach pain: Caffeine can stimulate the gastrointestinal tract, which can lead to nervousness, nausea, and diarrhea. Again, this can be very uncomfortable and boring. Some people have an innate oversensitivity to caffeine. Furthermore, combining coffee with Phentermine can double this effect.
  • Anxiety: If your morning joy (read: coffee) usually makes you wake up and start your day full of energy and motivation, this might change while on Phentermine. You might become anxious and nervous instead of motivated. The reason is simple: Phentermine and coffee lead to overstimulation of your central nervous system.
  • Heartburn: High acidity found in coffee can cause heartburn if combined with medications such as Phentermine. Of course, this is not a rule and not everyone will react the same. However, poor digestion and heartburn are some of the side effects of Phentermine and coffee consumption. You should visit your doctor and reduce the number of cups of coffee a day if you experience this issue while on Phentermine.
  • Insomnia: Coffee can motivate us, but it can also change our usual sleeping routine (6), especially while on Phentermine. As both of these substances are strong nervous system stimuli, avoid drinking coffee before going to bed. Try to calm yourself with a homemade, organic chamomile tea.

Recommendations and tips

As Phentermine and coffee act similarly on our nervous system, i.e., they both stimulate it, consulting your doctor and informing him/her on your caffeine intake habits before starting your Phentermine treatment is a good idea (7). Furthermore, both caffeine and Phentermine accelerate metabolism and increase the heart rate.

As each person reacts differently on Phentermine and on caffeine, you will perhaps not experience any side effects. On the other hand, if you are usually sensitive to caffeine, you should avoid combining these two substances.

If you handle caffeine very well, you don’t have to completely stop consuming coffee or tea with caffeine while on Phentermine. You can decrease the amount of caffeine you intake during the day. For example, if you usually consume three cups of coffee, you can drink only one cup in the morning while on Phentermine.

In conclusion, you can drink coffee while on Phentermine, especially if your body handles caffeine very well. However, you must be very cautious. You should inform your doctor about your coffee drinking habits before you start your Phentermine treatment. Also, decreasing the overall amount of coffee you consume per day while on Phentermine is an excellent idea.

References

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