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Benzphetamine (By mouth)

Benzphetamine (benz-FET-a-meen)

Used as part of a diet plan to help you lose weight.

Brand Name(s):

Didrex, Regimex

There may be other brand names for this medicine.

When This Medicine Should Not Be Used:

You should not use this medicine if you have had an allergic reaction or an unusual reaction to benzphetamine, other diet pills or amphetamines. Do not use this medicine if you are pregnant or plan to become pregnant. You should not use this medicine if you have a history of drug abuse, overactive thyroid, severe anxiety or glaucoma. Some people with high blood pressure or heart disease should not use this medicine. You should not use benzphetamine if you have used an MAO inhibitor (MAOI) such as Eldepryl®, Marplan®, Nardil®, or Parnate® within the past 14 days. Do not use this medicine if you are also using any other stimulants, such as caffeine, Ritalin®, other diet medicines, some asthma medicines, and some cough and cold medicines.

How to Use This Medicine:


  • Take your medicine as directed. This medicine is not for long-term use.Carefully follow your doctor's instructions about any special diet.

If a dose is missed:

  • Take a dose as soon as you remember. If it is almost time for your next dose, wait until then and take a regular dose. Do not take extra medicine to make up for a missed dose.

How to Store and Dispose of This Medicine:

  • Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.
  • Ask your pharmacist, doctor, or health caregiver about the best way to dispose of any outdated medicine or medicine no longer needed.
  • Keep all medicine out of the reach of children. Never share your medicine with anyone.

Drugs and Foods to Avoid:

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

  • Make sure your doctor knows if you are using other stimulants (such as caffeine, pemoline, Cylert®, Ritalin®, diet medicines, some asthma medicines, certain cough and cold medicines), insulin, or high blood pressure medicine (such as atenolol, lisinopril, Accupril®, Norvasc®, Toprol®).
  • Tell your doctor if you use medicine for depression (such as amitriptyline, nortriptyline, Norpramin®, Vivactil®), or medicines that change your urine (such as sodium bicarbonate, Pyridium®, Polycitra-K®, Urocrit-K®, UROQID-Acid®).

Warnings While Using This Medicine:

  • It is not safe to take this medicine during pregnancy. It could harm an unborn baby. Tell your doctor right away if you become pregnant.
  • Make sure your doctor knows if you are breast feeding, or if you have high blood pressure, diabetes, heart disease, liver disease, kidney disease, or a history of drug abuse.
  • If you have diabetes, this medicine may change the level of sugar in your blood or urine. Tell your doctor if you see changes in the results of your blood sugar or urine tests.
  • This medicine can be habit-forming. Do not use more than your prescribed dose. Call your doctor if you think your medicine is not working.
  • Do not stop using this medicine suddenly. Your doctor will need to slowly decrease your dose before you stop it completely.
  • This medicine should not be given to a child under 12 years old.
  • This medicine may make you dizzy or drowsy. Avoid driving, using machines, or doing anything else that could be dangerous if you are not alert.

Possible Side Effects While Using This Medicine:

Call your doctor right away if you notice any of these side effects:

  • Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
  • Chest pain.
  • Fast, pounding, or uneven heartbeat.

If you notice these less serious side effects, talk with your doctor:

  • Bad taste in your mouth, or dry mouth.
  • Change in sex drive.
  • Increased sweating.
  • Diarrhea or nausea.
  • Dizziness, nervousness, restlessness, headache, trembling, or trouble sleeping.

If you notice other side effects that you think are caused by this medicine, tell your doctor

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088

Last Updated: 4/4/2014

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