Adipex-P Side Effects

Generic name: phentermine

Medically reviewed by Drugs.com. Last updated on Nov 11, 2024.

Note: This document provides detailed information about Adipex-P.

Applies to phentermine: oral capsule, oral tablet Side Effects associated with phentermine. Some dosage forms listed on this page may not apply specifically to the brand name Adipex-P.

Applies to phentermine: oral capsule, oral tablet.

Precautions

It is very important that your doctor check your progress at regular visits to make sure that this medicine is working properly and does not cause any unwanted effects.

Do not use phentermine (the active ingredient contained in Adipex-P) if you are also using similar medicines such as benzphetamine, diethylpropion, mazindol, phendimetrazine, Bontril®, or Didrex®. Do not use this medicine if you also take an MAO inhibitor (MAOI), such as isocarboxazid (Marplan®), phenelzine (Nardil®,), selegiline (Eldepryl®), or tranylcypromine (Parnate®), or if you have used an MAOI within the past 14 days. Using these medicines together may cause serious unwanted effects.

Using this medicine while you are pregnant can harm your unborn baby. Use an effective form of birth control to keep from getting pregnant. If you think you have become pregnant while using this medicine, tell your doctor right away.

This medicine may be habit-forming. If you think this medicine is not working properly after you have taken it for a few weeks, do not increase the dose. Instead, check with your doctor.

Call your doctor right away if you notice a decrease in your ability to exercise, or if you faint, have chest pain, swelling of your feet or lower legs, or trouble with breathing. These may be symptoms of a very serious heart or lung problem.

This medicine may cause some people to become dizzy, lightheaded, or less alert than they are normally. Make sure you know how you react to this medicine before you drive, use machines, or do anything else that could be dangerous if you are dizzy or not alert.

This medicine may affect blood sugar levels. Diabetic patients may notice a change in blood or urine sugar tests. Check with your doctor if you have any questions.

Avoid drinking alcohol while you are using this medicine.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription and nonprescription (over-the-counter) medicines, dietary supplements, herbal remedies, or medicines for appetite control, asthma, colds, cough, hay fever, and sinus problems.

Serious side effects of Adipex-P

Along with its needed effects, phentermine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking phentermine:

Other side effects of Adipex-P

Some side effects of phentermine may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

For healthcare professionals

Applies to phentermine: compounding powder, oral capsule, oral capsule extended release, oral tablet, oral tablet disintegrating.

General adverse events

The more commonly reported adverse reactions have included palpitations, restlessness, insomnia, and headache.

Cardiovascular

• Frequency not reported: Regurgitant cardiac valvular disease, primary pulmonary hypertension, palpitations, tachycardia, elevated blood pressure, precordial pain, ischemic events, angina, myocardial infarction, cardiac failure, cardiac arrest^[Ref]

Nervous system

• Frequency not reported: Overstimulation, restlessness, nervousness, dizziness, euphoria, dysphoria, tremor, headache, fatigue, cerebrovascular events^[Ref]

Psychiatric

• Frequency not reported: Insomnia, psychosis, impotence, libido changes, depression, hallucinations^[Ref]

Hypersensitivity

• Frequency not reported: Urticaria^[Ref]

Gastrointestinal

• Frequency not reported: Dry mouth, unpleasant taste, diarrhea, constipation, other gastrointestinal disturbances, nausea, vomiting, abdominal cramps^[Ref]

Dermatologic

• Frequency not reported: Rash^[Ref]

Genitourinary

• Frequency not reported: Micturition disturbances^[Ref]

Other

• Frequency not reported: Facial edema^[Ref]

See also:

Frequently asked questions

• Why is phentermine a controlled substance?

Further information

Adipex-P side effects can vary depending on the individual. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Note: Medication side effects may be underreported. If you are experiencing side effects that are not listed, submit a report to the FDA by following this guide.

Medical Disclaimer