Phendimetrazine is a sympathomimetic amine, which is similar to an amphetamine. It is also known as an "anorectic” or "anorexigenic” drug. 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 other than those listed in this medication guide.

Take phendimetrazine exactly as directed by your doctor. If you do not understand these directions, ask your pharmacist, nurse, or doctor to explain them to you.

Take each dose with a full glass of water.

Phendimetrazine is usually taken once a day (sustained release formula) or two to three times daily (immediate-release formula) before meals on an empty stomach.

Do not take phendimetrazine in the evening because it may cause insomnia.

Do not crush, chew, or open any "once-daily” phendimetrazine tablets or capsules. Swallow them whole.

Never take more of this medication than is prescribed for you. Too much phendimetrazine could be very dangerous to your health.

Store phendimetrazine at room temperature away from moisture and heat.

You cannot take phendimetrazine if you have taken a monoamine oxidase inhibitor (MAOI) such as isocarboxazid (Marplan), tranylcypromine (Parnate), or phenelzine (Nardil) in the last 14 days.

Changes in insulin and other diabetes drug therapies may be necessary during treatment with phendimetrazine.

Phendimetrazine may reduce the effects of guanethidine (Ismelin). This could lead to an increase in blood pressure. Tell your doctor if you are taking guanethidine.

Before taking this medication, tell your doctor if you are taking a tricyclic antidepressant such as amitriptyline (Elavil), amoxapine (Asendin), doxepin (Sinequan), nortriptyline (Pamelor), imipramine (Tofranil), clomipramine (Anafranil), protriptyline (Vivactil), or desipramine (Norpramin). These drugs may decrease the effects of phendimetrazine.

Drugs other than those listed here may also interact with phendimetrazine. Talk to your doctor and pharmacist before taking any prescription or over-the-counter medicines.

Use caution when driving, operating machinery, or performing other hazardous activities. Phendimetrazine may cause dizziness, blurred vision, or restlessness, and it may hide the symptoms of extreme tiredness. If you experience these effects, avoid hazardous activities.

Do not take phendimetrazine late in the day. A dose taken too late in the day can cause insomnia.

Seek emergency medical attention.

Symptoms of a phendimetrazine overdose include restlessness, tremor, rapid breathing, confusion, hallucinations, panic, aggressiveness, nausea, vomiting, diarrhea, an irregular heartbeat, and seizures.

Take the missed dose as soon as you remember. However, if it is almost time for your next dose or if it is already evening, skip the missed dose and take only your next regularly scheduled dose. A dose taken too late in the day will cause insomnia. Do not take a double dose of this medication.

Use caution when driving, operating machinery, or performing other hazardous activities. Phendimetrazine may cause dizziness, blurred vision, or restlessness, and it may hide the symptoms of extreme tiredness. If you experience these effects, avoid hazardous activities.

Phendimetrazine is habit forming. You can become physically and psychologically dependent on this medication, and withdrawal effects may occur if you stop taking it suddenly after several weeks of continuous use. Talk to your doctor about stopping this medication gradually.

Do not crush, chew, or open any "once-daily” phendimetrazine tablets or capsules. Swallow them whole.

You cannot take phendimetrazine if you

• have heart disease or high blood pressure;

• have arteriosclerosis (hardening of the arteries);

• have glaucoma;

• have taken a monoamine oxidase inhibitor (MAOI) such as isocarboxazid (Marplan), tranylcypromine (Parnate), or phenelzine (Nardil) in the last 14 days; or

• have a history of drug or alcohol abuse.

Before taking this medication, tell your doctor if you have

• problems with your thyroid,

• an anxiety disorder,

• epilepsy or another seizure disorder, or

• diabetes.

You may not be able to take phendimetrazine, or you may require a lower dose or special monitoring during treatment if you have any of the conditions listed above.

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.

Your pharmacist has more information about phendimetrazine written for health professionals that you may read.

Phendimetrazine is available with a prescription under several brand names. The immediate-release formulation is available in 35 mg tablets and capsules. The sustained-release formulation is available in 105 mg capsules. Other brand or generic formulations may also be available. Ask your pharmacist any questions you have about this medication, especially if it is new to you.