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Updated on October 2, 2023
7 min read

Is It Safe to Drink Alcohol While Taking Phentermine?

What is Phentermine?

Phentermine (Adipex-P) is a prescription drug that belongs to the class of monoamine alkaloid derivatives. It’s a sympathomimetic stimulant, which acts as an effective appetite suppressant. Because it can decrease hunger, other people consider it a weight loss drug or diet pill.

Phentermine is a Schedule IV controlled substance. This is usually a classification for medication with high abuse potential. However, there’s little evidence that this is true for phentermine. 


What is Phentermine For?

Phentermine is a medication primarily for weight loss. It’s for people who are obese and have struggled to lose weight with other diet and exercise programs. 

You should take Phentermine along with proper diet and exercise. It’s important to note that the drug isn’t for those who only want to lose a few pounds.

Phentermine can cost around $21 to $24. Physicians typically prescribe it for a duration of up to 12 weeks.


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How Does Phentermine Work?

Phentermine functions by blocking the hunger signals in the brain. It achieves this by enhancing the body’s release of catecholamines.

Catecholamines are chemicals that the adrenal glands produce. The resulting hormonal effects include reduced appetite and elevated heart rate. Taking Phentermine triggers the release of norepinephrine (noradrenaline) and dopamine.

These are neurotransmitters that play a crucial role in regulating appetite and satiety. Dopamine helps reduce food cravings, while norepinephrine increases energy levels and metabolism.

Can You Drink Alcohol While Taking Phentermine?

Although it’s possible to drink alcohol while taking phentermine, it’s generally recommended that you refrain from doing so. This is because alcohol can interact with phentermine, which can cause unwanted side effects.

The main issue with alcohol mixing phentermine is that alcohol can intensify phentermine’s side effects. Mixing alcohol with phentermine can also increase the risk of developing side effects. Overall, healthcare providers recommend avoiding alcohol while taking phentermine.


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What are the Side Effects of Mixing Alcohol and Phentermine?

There are several risks of combining alcohol and phentermine. In addition to exacerbating existing side effects, doing so can cause:

  • Gastrointestinal problems (stomachaches, nausea, and heartburn)
  • Cardiovascular issues (increased risk of heart failure, heart rate, and blood pressure)
  • Chest pain
  • Dizziness or drowsiness
  • Depression
  • Concentration issues

Furthermore, mixing phentermine with other benign substances can result in harmful interactions. These include ginseng, guarana, sage, and yerba mate.


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Understanding Alcohol’s Impact on the Body

Alcohol affects various bodily functions, including the liver, brain, and digestive system. When you consume alcohol, the bloodstream absorbs it quickly and travels to different organs.

The Liver

The liver is responsible for breaking down alcohol into acetaldehyde and further metabolizing it into acetic acid. This process can take up to two hours per drink.

Excessive amounts of alcohol can lead to fatty liver disease and cirrhosis. These are both severe health conditions that can impact the liver’s functioning.

The Brain

Alcohol is a depressant that affects the central nervous system (CNS). It suppresses brain activity, resulting in slower reaction times and impaired judgment.

It also alters neurotransmitter levels, which can lead to mood changes or feelings of euphoria. However, consuming too much alcohol can also cause depression and anxiety.

The Digestive System

Alcohol consumption can irritate the digestive tract, leading to stomachaches, nausea, and heartburn. It can also damage the lining of the stomach and intestines.

This damage can result in digestive issues such as diarrhea, constipation, and bloating. Additionally, alcohol can interfere with the absorption of nutrients from food. This can lead to nutrient deficiencies and other health problems.

How Long Should You Wait to Drink Alcohol?

The effects of phentermine last for about 12 hours. This means you must wait 12 to 13 hours before drinking alcohol. If you want to avoid experiencing severe side effects, ensure phentermine has left your body before you start drinking alcohol.

What are the Side Effects of Phentermine?

Phentermine is generally a safe, effective drug that helps clinically obese people to lose weight. However, some may experience side effects while taking this medication. 

Common side effects are mild and include:

  • Elevated heart rate
  • Tingling in the hands or feet
  • Dry mouth
  • Sleeplessness
  • Nervousness
  • Constipation
  • Hyperactivity
  • Excitement
  • Headache

Less Common Side Effects of Phentermine

Other less common side effects may include:

  • Blurred vision
  • Decreased sex drive
  • Diarrhea
  • Gastrointestinal discomfort
  • Pain when urinating
  • Hair loss
  • Hypertension (high blood pressure)
  • Difficulty sleeping
  • Muscle pain
  • Heart palpitations
  • Tremors
  • Skin rash
  • Nausea
  • Vomiting

There is also a risk of more serious side effects when taking phentermine. These include heart valve disorders and psychotic disorders.

How Does Alcohol Affect Weight Loss?

While there are disputed benefits of moderate alcohol use, it can also make it more challenging to lose weight. There are several reasons why consuming alcohol may hinder weight loss and lead to weight gain. 

Alcohol contains 82 calories per ounce. In addition, the amount of calories increases depending on the drink. Drinking more than a moderate amount of alcohol can contribute to weight gain in people across all health backgrounds.

Effects of Alcohol on Metabolism and Fat Storage 

Drinking alcohol to the point of intoxication also makes it easier to overeat, leading to increased fat storage. Alcohol also increases metabolic rate, causing it to burn calories rather than store them as fat.

However, sugar consumption also decreases when alcohol is present. This means your body will store more fat until the body processes alcohol.

Treatment for Alcohol Abuse

Phentermine and alcohol addiction are serious problems that can affect your life. The first step in treating alcohol and substance abuse is to seek help from a qualified professional. 

A doctor or addiction specialist can provide a personalized treatment plan to address the root causes of your drinking problem. Treatment options for alcohol abuse include the following:

  • Counseling: Working with a counselor helps explore the underlying issues causing your drinking problem, such as stress or other mental health issues.
  • Medications: Some treatments use drugs to reduce the urge to drink and help manage withdrawal symptoms.
  • Detoxification: This involves removing all traces of alcohol from your body so that you can resume normal activities.
  • Behavioral therapy: You can use behavioral therapy to learn new coping skills and find healthier ways to deal with stressors or triggers that may lead to drinking.
  • Group support: Joining a support group, like Alcoholics Anonymous (AA), can provide social connections and accountability.

Tips for the Safe Use of Phentermine

To ensure you’re taking phentermine safely, follow these guidelines:

  • Don’t exceed the recommended dosage: Taking more than your doctor prescribed can lead to serious side effects.
  • Avoid consuming alcohol while on phentermine: Alcohol can interact with this medication and increase the risk of harmful side effects.
  • Take phentermine as directed by your doctor: Don’t take more than or for longer than your physician prescribed.
  • Store phentermine safely: Keep it out of reach of children and store it at room temperature away from heat, light, and moisture.
  • Take the drug properly: Don’t chew, crush, break, or open them. Swallow them whole with water.
  • Follow your doctor’s recommendation regarding diet and exercise: Phentermine is most effective when you combine it with a healthy diet and regular exercise.
  • Take the last dose four to six hours before bedtime: Taking phentermine close to bedtime can cause sleep disturbances.

Consult your doctor if you have concerns or questions about taking phentermine safely. They can guide you on using this medication to maximize its benefits and minimize risks.

Tips for Safe Alcohol Consumption

Drinking in moderation and understanding the effects of alcohol can help prevent health problems from excessive drinking. Here are some tips for safe alcohol consumption:

  1. Know your limits: The recommended daily limit is one drink for women and two for men.
  2. Understand units of alcohol: One unit of alcohol equals 10ml or 8g of pure alcohol.
  3. Pace yourself: Drink slowly and alternate with non-alcoholic beverages to stay hydrated.
  4. Avoid binge drinking: Binge drinking is consuming large quantities of alcohol in a short period, which can lead to serious health issues.
  5. Take breaks from drinking: Give your body time to recover by having several days without alcohol each week.
  6. Avoid mixing alcohol and medications: Alcohol can interact with certain medications, causing harmful side effects.
  7. Seek help if you need it: If you’re struggling with controlling your drinking, seek help from a medical professional or support group.


Phentermine is a stimulant drug that can suppress appetite, helping you lose weight. While the drug is safe alone, it can cause serious side effects and harmful interactions.

In addition, drinking too much alcohol affects your weight loss efforts. Remember to drink alcohol moderately when prescribed phentermine to avoid health problems or complications.

If you suspect you or a loved one suffers from drug or alcohol abuse, seek professional help immediately. Various treatments are available to help you overcome this problem. 

Updated on October 2, 2023
8 sources cited
Updated on October 2, 2023
All Alcoholrehabhelp content is medically reviewed or fact checked to ensure as much factual accuracy as possible.

We have strict sourcing guidelines and only link to reputable media sites, academic research institutions and, whenever possible, medically peer reviewed studies.
  1. Johnson et al. “Topiramate And Phentermine.” StatPearls Publishing, 2023. 

  2. Jordan et al. “Cardiovascular effects of phentermine and topiramate: a new drug combination for the treatment of obesity.” Journal of Hypertension, 2014. 

  3. “PubChem Compound Summary for CID 4771, Phentermine.” National Center for Biotechnology Information, 2023.

  4. Li et al. “Anti-Obesity Drugs for Obese Women Planning Pregnancy.” Obesity, 2013. 

  5. Cosentino et al. “Phentermine and topiramate for the management of obesity: a review.” Drug Design, Development and Therapy, 2013.

  6. “Suprenza.” United States Food and Drug Administration, 2013.

  7. “Phentermine.” ClinCalc DrugStats Database, 2022.

  8. Phentermine (Oral Route).” Mayo Clinic, 2023.

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All content created by Alcohol Rehab Help is sourced from current scientific research and fact-checked by an addiction counseling expert. However, the information provided by Alcohol Rehab Help is not a substitute for professional treatment advice.
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