Phentermine and Alcohol: a safe or dangerous mix interaction?

January 9, 2024 |

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Phentermine is an FDA-approved obesity drug, while alcohol is a recreational drink. Both can be addictive, but what happens if you take them at the same time?

Is the phentermine and alcohol combination safe or dangerous?

The answer is pretty simple: this combination can be dangerous. Aside from both being addictive on their own and could likely increase the risks of dependence, taking them together can lead to an increased risk of cardiovascular side effects, such as chest pains and elevated blood pressure. Even a small amount of alcohol can amplify phentermine’s side effects, possibly leading to a heart attack or stroke. The worst-case scenario can even lead to death.

That should really be enough to warn you against taking these two together, right?

But you might also wonder whether the combination can cause other side effects, whether alcohol can inhibit weight loss, and what alternative you should try instead of using phentermine.

Keep reading to find out.

Can you Drink Alcohol While Taking Phentermine?

No. We’ve established above that combining alcohol with phentermine can be really dangerous. Each one has its side effects. Many doctors even warn against using phentermine, even on its own, because it can have dangerous side effects and risks.

Taking these two together can amplify their negative effects, which may lead to a life-changing medical emergency such as a stroke.

It’s just not worth it.

However, don’t panic just in case you accidentally took the two and you’re now trying to find out about their effects on your body.

A lot of people tend to forget about drug interactions and how drinking alcohol can pose serious health risks if you’re taking any prescription medication.

If you had taken the combination by accident, it’s best to seek medical attention immediately or ask someone to help monitor your vital signs. Your doctor will know what to do.

Effects of Combining Alcohol & Phentermine

1. Central Nervous System (CNS) Effects

So, you might be wondering whether you’ll feel “high” or “low.”

The answer actually depends on several factors, especially because alcohol is considered a “downer” that might make you feel low or sad, while phentermine is a stimulant that can make you feel “high.”

Phentermine can also give you an energy boost to power up your workout routines, but alcohol can make you feel tired – both while you’re drinking it and the day after as you nurse your hangover.

The mixed messages from these two different substances can confuse your body.

Effects on your central nervous system can lead to the following:

  • Drowsiness
  • Depression
  • Difficulty concentrating
  • Dizziness

It’s very important to avoid driving, operating machinery and hazardous equipment, or any other activity that requires concentration after drinking alcohol, taking phentermine, and especially if you combined the two.

2. Multiple Substance Abuse

Both alcohol and phentermine have the potential for abuse, but their combination could lead to multiple substance abuse. That means that you could become dependent on not just one but two substances.

Multiple or polysubstance abuses happen when you abuse more than one substance at a time, intentionally or unintentionally.

Polysubstance abuse requires treatment in a professional setting. Ask your doctor about it.

3. Cardiovascular Side Effects

Any side effect that affects the heart can be potentially dangerous. After all, your life ends once your heart fails and stops beating!

Combining alcohol with phentermine can lead to the following:

  • Chest pain
  • Increased heart rate
  • Abnormal increases in blood pressure
  • Heart failure, especially if you have an underlying medical condition (e.g., heart disease)

Note that even on its own, phentermine can be dangerous to anyone with a heart condition. It can also make you develop a heart problem even if you had a healthy heart.

Signs of a heart-related emergency include the following:

  • Fast or abnormal heartbeat
  • Dizziness
  • Trouble breathing
  • Chest pain
  • Shakiness
  • Fatigue (a weakness that doesn’t go away)
  • Unexplained swelling in your arms or legs

4. Psychological Effects

Phentermine is known to cause depression, anxiety, and other mental illnesses. These negative feelings can be intensified by alcohol.

On the other hand, alcohol can also reduce inhibitions. So, you are more likely to make irrational decisions that could affect your body. For example, while phentermine suppresses appetite, drinking alcohol might make you want to eat more or forget that you were on a diet in the first place.

5. Gastrointestinal Effects

Mixing these two substances can lead to the following gastrointestinal side effects:

  • Heartburn
  • Stomachache
  • Nausea
  • Vomiting

These happen because alcohol can irritate the lining of your stomach.

Note that alcohol can also affect your liver and might make it more difficult for your body to burn fat.

6. Inhibit Weight Loss

Take note that it’s best to avoid alcohol if you’re trying to lose weight.

This recreational drink contains a lot of empty calories and a possibly large amount of sugar. So, drinking an alcoholic drink is counterproductive and could just actually make you gain back some of the weight you lost from drinking phentermine.

Here are some of the calorie contents of popular alcoholic drinks:

  • Long Island Iced Tea – 424 calories
  • Mojito – 242 calories
  • Double vodka & coke – 168 calories
  • Beer (12-oz can) – 155 calories
  • Red wine (5-oz glass) – 125 calories

So, mixing these two can cancel out the weight-loss journey you’ve worked hard to achieve, leading to bad results.

7. Risks for Obese Individuals

Those who are obese (BMI over 30) already have an increased risk for stroke, high blood pressure, and cardiovascular diseases.

Moreover, phentermine can also cause heart problems or worsen a cardiovascular condition.

So, the combination should be avoided because it can dangerous to your heart.

Mixing phentermine and alcohol increases your risks by tenfold.

Phentermine And Alcohol: Overdose (abuse & other risks)

Possible Overdose

A combination of these two substances will mix and amplify each other’s risks. So, it can lead to a drug overdose even if you aren’t taking double your phentermine dose.

Watch out for the following signs and symptoms of drug overdose:

  • Confusion
  • Hallucinations (auditory or visual)
  • Panic
  • Depression
  • Significant changes in mood
  • Fatigue
  • Weak pulse
  • Irregular heartbeats
  • Diarrhea
  • Stomach cramps
  • Nausea and vomiting
  • Slow or stopped breathing
  • Seizures

Drug overdose can lead to coma or death.


Both alcohol and phentermine have the potential for abuse, even on their own. But using them in combination can lead to multiple dependence and an increased risk for addiction.

Treatment for Alcoholism & Phentermine Addiction

There are different ways to treat addiction or dependence on alcohol and phentermine, depending on your symptoms and other factors.

Your doctor might consider the following:

  • Counseling and behavioral therapy – address the underlying reason for drug use and also help you deal with the symptoms
  • Drug detox – the withdrawal symptoms can be dangerous, so it’s important to seek medical attention to help your body get rid of phentermine and alcohol in its system

Treatment for either or both alcoholism and phentermine addiction can be a long process, especially if you experienced the symptoms for months.

Your doctor won’t abruptly get you off the substances you’re addicted to because the withdrawal symptoms can be severe. It’s possible that they’ll taper off or gradually decrease the dosage, as in the case of phentermine, so you won’t experience several withdrawal symptoms.

Alternative Weight-Loss Drug To Phentermine

With so many bad effects relating to phentermine, we suggest avoiding it altogether.

We recommend PhenQ, instead.

Like phentermine, PhenQ is an appetite suppressant that helps you lose weight by making you feel fuller for a longer time. If you’re full, then you won’t be tempted to eat a lot of food. The less you eat, the more weight you can shed off with exercise.

With its caffeine content and propriety blend of stimulants, PhenQ can give you an energy boost to get you ready for an intense workout session that’s perfect for losing weight.

What makes PhenQ much better than phentermine is that you can get it without a prescription, it isn’t potentially addictive, and it doesn’t have known side effects or withdrawal symptoms.

But how about alcohol and PhenQ?

While alcohol isn’t likely to reduce the effects of PhenQ, we advise against taking them together.

In fact, we recommend that you avoid alcohol if you’re trying to lose weight. After all, as we already established above, alcohol can make you gain weight. Your weight loss regimen can work better if you avoid drinking alcohol.


Can You Have A Glass Of Wine While Taking Phentermine?

No. Wine also contains alcohol – most wines even have a higher alcohol content than beer. So, drinking even just a glass of wine can lead to dangerous side effects if you’re also taking phentermine.

How Long After Phentermine Can I Drink Alcohol?

As much as possible, don’t mix phentermine with alcohol. Wait at least 12 hours after taking phentermine before you drink alcohol.

In the same way, you should also wait 12 hours after drinking alcohol before you take phentermine.

You’ll need at least 12 hours because the effects of phentermine can last long, especially if you’re taking extended-release or sustained-release phentermine.

Should I Stop Taking Phentermine If I Want To Drink Alcohol?

Well, this can be tricky. If you really, really want to drink some alcohol, then you should consider stopping your phentermine intake. However, abruptly stopping phentermine use or missing a dose can cause withdrawal symptoms that can affect your body, mood, and memory.

The most common withdrawal symptoms can include the following:

  • Headaches
  • Fatigue or low energy
  • Diarrhea
  • Stomach pain
  • Vomiting
  • High blood pressure
  • Irregular, rapid heartbeat
  • Insomnia
  • Loss of memory
  • Menstrual abnormalities

However, phentermine can also cause serious withdrawal symptoms, especially if you’ve been taking it at higher doses regularly or for an extended period:

  • Tremors
  • Nerve damage
  • Seizures
  • Congestive heart failure
  • Stroke
  • Cardiac arrest

Remember that cardiac arrest can be fatal because it leads to loss of heart function.

So, it might be best to just stop considering taking alcohol at any given time that you’re taking phentermine.

What Should You Not Drink With Phentermine?

Phentermine has many contraindications because it can interact with a wide variety of substances.

As you learned above, you shouldn’t mix phentermine with alcohol of any form.

It’s very important to also avoid drinking coffee and other caffeinated drinks (including tea, energy drinks, pre-workout supplements, etc.) because these are stimulants like phentermine. Taking them together can also lead to dangerous side effects.

Don’t drink the following herbal medications or natural supplements if you’re taking phentermine:

  • American ginseng
  • Guarana
  • Eucalyptus
  • Yerba mate
  • Sage

Drugs or medications you should also avoid taking together with phentermine:

  • Oral contraceptives (because they might cause irregular bleeding)
  • Amphetamine
  • Antacids
  • Epinephrine
  • Dopamine
  • Linezolid
  • Procarbazine
  • Tranylcypromine
  • Selegiline
  • Rasagiline
  • Amantadine
  • Desmopressin
  • Antihypertensives (such as beta-blockers)
  • CNS (central nervous system) depressants such as benzodiazepines, barbiturates, and sleep medications
  • SSRIs – selective serotonin reuptake inhibitors such as Paxil (paroxetine), Prozac (fluoxetine), Luvox (fluvoxamine), and Zoloft (sertraline)
  • MAOIs – monoamine oxidase inhibitors such as Marplan (isocarboxazid) and Nardil (phenelzine)

Our Final Thoughts

So, what’s the verdict? Is it safe to drink alcohol while taking phentermine? The answer is an unequivocal no. Mixing alcohol and phentermine can have dangerous consequences for your health, including liver damage and increased blood pressure.

If you are taking phentermine, it’s best to avoid drinking altogether.

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