What is 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 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 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:
coronary artery disease (hardening of the arteries);
heart disease;
severe or uncontrolled high blood pressure;
overactive thyroid;
glaucoma;
if you have a history of drug or alcohol abuse; or
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:
high blood pressure;
diabetes; or
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.