• Basic Info
• Top Questions
• Interactions

How should I take phendimetrazine?

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.

What happens if I miss a dose?

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.

What happens if I overdose?

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.

What should I avoid while taking phendimetrazine?

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.

What are the possible side effects of phendimetrazine?

If you experience any of the following serious side effects, stop taking phendimetrazine and seek emergency medical attention:

• an allergic reaction (difficulty breathing; closing of your throat; swelling of your lips, tongue, or face; or hives);

• an irregular heartbeat or very high blood pressure (severe headache, blurred vision); or

• hallucinations, abnormal behavior, or confusion.

Other, less serious side effects may be more likely to occur. Continue to take phendimetrazine and talk to your doctor if you experience

• restlessness or tremor,

• nervousness or anxiety,

• headache or dizziness,

• insomnia,

• dry mouth or an unpleasant taste in your mouth,

• diarrhea or constipation, or

• impotence or changes in your sex drive.

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.

Side effects other than those listed here may also occur. Talk to your doctor about any side effect that seems unusual or that is especially bothersome.