Adipex

Adipex Overview

Adipex-P (generic: phentermine) is a prescription medicine used for weight loss.  It is taken for a limited amount of time by overweight adults, along with exercise and a low-fat diet. Adipex-P belongs to a group of drugs called anorectics. It works by decreasing appetite.

Adipex-P comes in tablet and capsule form.  It usually taken by mouth once daily, in the morning.

Common side effects of Adipex-P include high blood pressure, fast heart beat, insomnia, and dizziness.

Uses of Adipex

Adipex-P is a prescription medicine used to help adults lose weight.  It is taken for a limited amount of time by overweight people who are exercising and eating a low-calorie diet.

This medication may be prescribed for other uses.  Ask your doctor or pharmacist for more information.

Side Effects of Adipex

Common side effects include:

  • High blood pressure
  • fast heart beats
  • insomnia
  • dizziness
  • rash
  • diarrhea
  • tremors
  • constipation

This is not a complete list of Adipex-P side effects. Ask your doctor or pharmacist for more information.

Adipex Interactions

Tell your doctor about all the medicines you take including prescription and nonprescription medications, vitamins, and herbal supplements. Especially tell your doctor if you take:

  • fluoxetine (Prozac)
  • fluvoxamine (Luvox) 
  • guanethidine
  • insulin (you may need to increase your dose of insulin while taking Adipex-P)
  • medications for weight loss and depression
  • paroxetine (Paxil)
  • sertraline (Zoloft)
  • monoamine oxidase (MAO) inhibitors such as isocarboxazid (Marplan), phenelzine (Nardil), selegiline (Eldepryl, Emsam, Zelapar) and tranylcypromine (Parnate)

This is not a complete list of Adipex-P drug interactions. Ask your doctor or pharmacist for more information.

Adipex Precautions

Adipex-P can cause primary pulmonary hypertension, a rare but serious and sometimes fatal side effect. This is a condition where the pressure of the arteries in your lungs increases, causing more pressure on your heart which can lead to heart failure and death. The first symptoms is often shortness of breath or lightheadedness during activity. Other symptoms include:

  • ankle and leg swelling
  • bluish color of the lips or skin 
  • chest pain or pressure, usually in the front of the chest
  • dizziness or fainting spells
  • tiredness
  • increased abdomen size
  • weakness

You should not take Adipex-P if you have:

  • heart disease
  • lung disease
  • hyperthyroidism
  • glaucoma
  • a history of drug abuse or dependence
  • depression being treated with certain antidepressant medications called MAOI inhibitors

Adipex should not be used during pregnancy or while breastfeeding.

Adipex Food Interactions

While there are no specific Adipex-P food interactions, you should avoid drinking large amounts of beverages containing caffeine (coffee, tea, colas) or eating large amounts of chocolate while taking Adipex-P as caffeine can increase the side effects of this medicine.

Inform MD

Before taking Adipex-P tell your doctor and pharmacist if you are allergic to Adipex-P, any other medications, or any of the ingredients in Adipex-P tablets or capsules. See "Forms of Medication".

Tell your doctor about all the medicines you take including prescription and non-prescription medicines, vitamins, and herbal supplements.

Also tell your doctor if you are taking monoamine oxidase (MAO) inhibitors such as isocarboxazid (Marplan), phenelzine (Nardil), selegiline (Eldepryl, Emsam, Zelapar) and tranylcypromine (Parnate), or if you have stopped taking one of these medications in the past 2 weeks. Your doctor may need to change the doses of your medications or monitor you carefully for side effects.

Tell your doctor if you have or have ever had:

  • heart disease
  • high blood pressure
  • arteriosclerosis (narrowing of the arteries)
  • hyperthyroidism (overactive thyroid gland)
  • diabetes
  • glaucoma
  • a history of drug abuse

Tell your doctor if you are pregnant, plan to become pregnant, or are breastfeeding. 

Adipex and Pregnancy

Tell your doctor if you are pregnant or if you are planning to become pregnant. It is not known if Adipex-P will harm your unborn baby.

Adipex and Lactation

Tell your doctor if you are breastfeeding or if you are planning to breastfeed. It is not known whether Adipex-P is excreted in breast milk or if it will harm your baby.

Adipex Usage

  • Adipex-P comes as tablets and extended-release capsules.
  • It usually is taken as a single daily dose in the morning or three times a day 30 minutes before meals.
  • Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take Adipex-P exactly as directed.
  • Most people take Adipex-P for 3-6 weeks.
  • The length of treatment depends on how you respond to the medication. Adipex-P can be habit-forming.
  • Do not take a larger dose, take it more often, or take it for a longer period than your doctor tells you to.
  • If you are taking the extended-release (long-acting) tablets, do not split, chew, or crush them tablet. There are some tablets that can be crushed and mixed with food.

Adipex Dosage

Take Adipex-P exactly as your doctor has prescribed it. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. 

The usual adult dose is one capsule or tablet (37.5 mg) daily, taken before breakfast or 1 to 2 hours after breakfast. For tablets, the dosage may be adjusted as needed. For some people ½ tablet (18.75 mg) daily may be sufficient, while in some cases it may be best to give ½ tablet (18.75 mg) two times a day.

Follow the diet and exercise program your doctor has given you. Adipex-P works best in combination with a diet program.

Adipex Overdose

If you have taken too much Adipex-P call your local Poison Control Center or seek emergency medical attention right away.

 

Forms of Adipex

Adipex-P is available as a capsule or a tablet containing 37.5 mg of phentermine hydrochloride (equivalent to 30 mg phentermine base).

Inactive ingredients: corn starch, anhydrous lactose, magnesium stearate, microcrystalline cellulose, sucrose, and FD&C Blue No. 1

Other Requirements

Keep Adipex-P in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom). Throw away any medication that is outdated or no longer needed. Talk to your pharmacist about the proper disposal of your medication.

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Reviewed by: 
Beth Bolt, RPh
Last Updated:
June 17, 2013