Phendimetrazine is similar to an amphetamine. Phendimetrazine stimulates the central nervous system (nerves and brain), which increases your heart rate and blood pressure and decreases your appetite.

Phendimetrazine is used as a short-term supplement to diet and exercise in the treatment of obesity.

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

Phendimetrazine may cause blurred vision or impair your thinking or reactions. Be careful if you drive or do anything that requires you to be alert and able to see clearly.

Phendimetrazine may be habit-forming and should be used only by the person it was prescribed for. Keep the medication in a secure place where others cannot get to it.

Do not stop using phendimetrazine suddenly after long-term use, or you could have unpleasant withdrawal symptoms. Ask your doctor how to avoid withdrawal symptoms when you stop using phendimetrazine.

Do not crush, chew, break, or open the extended-release capsule. Swallow it whole. Breaking or opening the pill may cause too much of the drug to be released at one time.

Do not use phendimetrazine 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.

You should not use this medication if you are allergic to phendimetrazine, or if you have:

• coronary artery disease (hardening of the arteries);

• heart disease;

• severe or uncontrolled high blood pressure;

• heart murmur or heart valve disorder;

• pulmonary arterial hypertension (PAH);

• overactive thyroid;

• glaucoma;

• severe agitation or nervousness;

• 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 phendimetrazine, tell your doctor if you have any of these other conditions:

• high blood pressure;

• diabetes;

• an anxiety disorder;

• epilepsy or seizure disorder; or

• if you have used other diet pills in the past year (prescription, over-the-counter, or herbal products).

It is not known whether phendimetrazine will harm an unborn baby. Do not take phendimetrazine without first talking to your doctor if you are pregnant.

It is also not known whether phendimetrazine passes into breast milk. Do not take phendimetrazine without first talking to your doctor if you are breast-feeding a baby.