Adipex-P

Generic Name: phentermine (FEN ter meen)

Brand Names: Adipex-P, Oby-Cap, T-Diet, Zantryl

What is Adipex-P (phentermine)?

Phentermine is a stimulant that is similar to an amphetamine. Phentermine is an appetite suppressant that affects the central nervous system.

Phentermine is used together with diet and exercise to treat obesity (overweight) in people with risk factors such as high blood pressure, high cholesterol, or diabetes.

Phentermine may also be used for purposes not listed in this medication guide.

What is the most important information I should know about Adipex-P (phentermine)?

Do not use phentermine if you have used an MAO inhibitor such as furazolidone (Furoxone), isocarboxazid (Marplan), phenelzine (Nardil), rasagiline (Azilect), selegiline (Eldepryl, Emsam, Zelapar), or tranylcypromine (Parnate) in the last 14 days. A dangerous drug interaction could occur, leading to serious side effects. Taking phentermine together with other diet medications such as fenfluramine (Phen-Fen) or dexfenfluramine (Redux) can cause a rare fatal lung disorder called pulmonary hypertension. Do not take phentermine with any other diet medications without your doctor's advice. Phentermine may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be alert. Drinking alcohol can increase certain side effects of phentermine.

Phentermine is only part of a complete program of treatment that may also include diet, exercise, and weight control. Follow your diet, medication, and exercise routines very closely.

Phentermine may be habit-forming and should be used only by the person it was prescribed for. Never share phentermine with another person, especially someone with a history of drug abuse or addiction. Keep track of the amount of medicine used from each new bottle. Phentermine is a drug of abuse and you should be aware if anyone is using your medicine improperly or without a prescription. Do not stop using phentermine suddenly, or you could have unpleasant withdrawal symptoms. Ask your doctor how to avoid withdrawal symptoms when you stop using phentermine.

What should I discuss with my healthcare provider before taking Adipex-P (phentermine)?

Do not use phentermine if you have used an MAO inhibitor such as furazolidone (Furoxone), isocarboxazid (Marplan), phenelzine (Nardil), rasagiline (Azilect), selegiline (Eldepryl, Emsam, Zelapar), or tranylcypromine (Parnate) in the last 14 days. A dangerous drug interaction could occur, leading to serious side effects.

Taking phentermine together with other diet medications such as fenfluramine (Phen-Fen) or dexfenfluramine (Redux) can cause a rare fatal lung disorder called pulmonary hypertension. Do not take phentermine with any other diet medications without your doctor's advice.

You should not take phentermine if you are allergic to it, or if you have:

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  coronary artery disease (hardening of the arteries);

  
  


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  heart disease;

  
  


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  severe or uncontrolled high blood pressure;

  
  


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  overactive thyroid;

  
  


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  glaucoma;

  
  


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  if you have a history of drug or alcohol abuse; or

  
  


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  if you are allergic to other diet pills, amphetamines, stimulants, or cold medications.

  
  

To make sure you can safely take phentermine, tell your doctor if you have any of these other conditions:

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  high blood pressure;

  
  


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  diabetes; or

  
  


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  a thyroid disorder.

  
  

FDA pregnancy category C. It is not known whether phentermine will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant while using this medication. Phentermine can pass into breast milk and may harm a nursing baby. You should not breast-feed while taking phentermine. Do not give this medication to a child younger than 16 years old. Phentermine may be habit-forming and should be used only by the person it was prescribed for. Never share phentermine with another person, especially someone with a history of drug abuse or addiction. Keep the medication in a place where others cannot get to it.

How should I take Adipex-P (phentermine)?

Take exactly as prescribed by your doctor. Do not take in larger or smaller amounts or for longer than recommended. Follow the directions on your prescription label.

It is best to take phentermine on an empty stomach before breakfast or within 2 hours after breakfast.

To prevent sleep problems, take this medication early in the day, no later than 6:00 pm.

Talk with your doctor if you have increased hunger or if you otherwise think the medication is not working properly. Taking more of this medication will not make it more effective and can cause serious, life-threatening side effects.

Phentermine should be taken only for a short time, such as a few weeks.

Do not stop taking phentermine suddenly, or you could have unpleasant withdrawal symptoms. Ask your doctor how to avoid withdrawal symptoms when you stop using phentermine. Store at room temperature away from moisture and heat. Keep track of the amount of medicine used from each new bottle. Phentermine is a drug of abuse and you should be aware if anyone is using your medicine improperly or without a prescription.

See also: Adipex-P dosage (in more detail)

What happens if I miss a dose?

Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222. An overdose of phentermine can be fatal.

Overdose symptoms may include confusion, hallucinations, panic, feeling hostile or aggressive, nausea, vomiting, diarrhea, stomach cramps, irregular heartbeat, rapid breathing, overactive reflexes, confusion, hallucinations, seizure (convulsions), feeling light-headed, or fainting.

What should I avoid while taking Adipex-P (phentermine)?

Drinking alcohol can increase certain side effects of phentermine. Phentermine may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be alert.

Adipex-P (phentermine) side effects

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat. Call your doctor at once if you have a serious side effect such as:

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  feeling short of breath, even with mild exertion;

  
  


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  chest pain, feeling like you might pass out;

  
  


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  swelling in your ankles or feet;

  
  


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  pounding heartbeats or fluttering in your chest;

  
  


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  confusion or irritability, unusual thoughts or behavior;

  
  


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  feelings of extreme happiness or sadness; or

  
  


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  dangerously high blood pressure (severe headache, blurred vision, buzzing in your ears, anxiety, confusion, chest pain, shortness of breath, uneven heartbeats, seizure).

  
  

Less serious side effects may include:

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  feeling restless or hyperactive;

  
  


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  headache, dizziness, tremors;

  
  


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  sleep problems (insomnia);

  
  


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  dry mouth or an unpleasant taste in your mouth;

  
  


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  diarrhea or constipation, upset stomach; or

  
  


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  increased or decreased interest in sex, impotence.

  
  

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What other drugs will affect Adipex-P (phentermine)?

Tell your doctor about all other medicines you use, especially:

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  blood pressure medications;

  
  


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  insulin or oral diabetes medication; or

  
  


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  an antidepressant such as citalopram (Celexa), fluoxetine (Prozac, Sarafem, Symbyax), paroxetine (Paxil), sertraline (Zoloft), and others.

  
  

This list is not complete and other drugs may interact with phentermine. Tell your doctor about all medications you use. This includes prescription, over-the-counter, vitamin, and herbal products. Do not start a new medication without telling your doctor.

More Adipex-P resources

• Adipex-P Side Effects (in more detail)
• Adipex-P Dosage
• Adipex-P Use in Pregnancy & Breastfeeding
• Drug Images
• Adipex-P Drug Interactions
• Adipex-P Support Group
• 145 Reviews for Adipex-P - Add your own review/rating

• Adipex-P MedFacts Consumer Leaflet (Wolters Kluwer)


• Adipex-P Prescribing Information (FDA)


• Phentermine Prescribing Information (FDA)


• Phentermine Monograph (AHFS DI)


• Fastin Advanced Consumer (Micromedex) - Includes Dosage Information


• Ionamin MedFacts Consumer Leaflet (Wolters Kluwer)


• Ionamin Prescribing Information (FDA)

Compare Adipex-P with other medications

• Obesity
• Weight Loss

Where can I get more information?

• Your pharmacist can provide more information about phentermine.

See also: Adipex-P side effects (in more detail)