Phendimetrazine (By mouth)


Phendimetrazine (fen-dye-MET-ra-zeen)

Used with a diet plan for weight loss. This medicine is an appetite suppressant.

Brand Name(s)

Bontril Slow-Release, Bontril PDM, Phendiet-105, Bontril, Phendiet

There may be other brand names for this medicine.

When This Medicine Should Not Be Used

Do not use this medicine if you have had an allergic reaction to phendimetrazine, or if you also use any other stimulant, diet pill, or similar medicine. You should not use this medicine if you are feeling agitated or if you have glaucoma, an overactive thyroid, a history of heart and blood vessel disease (such as uncontrolled high blood pressure, arrhythmia, clogged arteries, congestive heart failure, pulmonary hypertension, or stroke), or a history of drug abuse. Do not use this medicine if you are pregnant or breastfeeding. Do not use this medicine if you have used an MAO inhibitor such as Eldepryl®, Marplan®, Nardil®, or Parnate® within the past 14 days.

How to Use This Medicine

Capsule, Long Acting Capsule, Tablet

  • Your doctor will tell you how much of this medicine to use and how often. Do not use more medicine or use it more often than your doctor tells you to.This medicine should be used for only a few weeks, or until it no longer suppresses your appetite.
  • Take the medicine 30 to 60 minutes before a meal.
  • Swallow the capsule or extended-release capsule whole. Do not break, crush, or chew it.
  • Carefully follow your doctor's instructions for a reduced-calorie diet plan and regular exercise.

If a dose is missed:

  • If you miss a dose or forget to use your medicine, use it as soon as you can. If it is almost time for your next dose, wait until then to use the medicine and skip the missed dose. Do not use 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  • Ask your pharmacist, doctor, or health caregiver about the best way to dispose of any outdated medicine or medicine no longer needed.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 away from children and 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 also using guanethidine (Ismelin®), sibutramine (Meridia®), or insulin or diabetes medicine that you take by mouth (such as glyburide, glipizide, metformin, Actos®, or Glucotrol®).
  • Do not drink alcohol while you are using this medicine.

Warnings While Using This Medicine

  • Using this medicine while you are pregnant can harm your unborn baby. Use an effective form of birth control to keep from getting pregnant. If you think you have become pregnant while using the medicine, tell your doctor right away.
  • Make sure your doctor knows if you have kidney disease, diabetes, heart valve disease, or high blood pressure.
  • Check with your doctor right away if you notice a decrease in your ability to exercise, if you faint, or if you have chest pain, swelling of your feet or lower legs, or trouble breathing. These may be symptoms of a very serious heart or lung problem.
  • This medicine may be habit-forming. If you feel that the medicine is not working as well, do not use more than your prescribed dose. Call your doctor for instructions.
  • This medicine may make you dizzy or drowsy. Do not drive, use machines, or do anything else that could be dangerous if you are not alert.
  • Do not stop using this medicine unless your doctor tells you to. If you suddenly stop using this medicine, you may feel very tired and depressed.
  • Your doctor will need to check your blood pressure and heart rate at regular visits while you are using this medicine. Be sure to keep all appointments.

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
  • Change in how much or how often you urinate
  • Chest pain, shortness of breath, or trouble breathing
  • Confusion, feelings of panic, or seeing, hearing, or feeling things that are not there
  • Fast, pounding, or uneven heartbeat
  • Lightheadedness or fainting
  • Swelling of your feet or lower legs
  • Tremors or shaking

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

  • Dry mouth, constipation, diarrhea, nausea, or stomach pain
  • Feeling restless, excited, or agitated
  • Headache, blurred vision
  • Increased or decreased interest in sex
  • Mild problems sleeping
  • Sweating or flushing

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

Version Info

  • Last Reviewed on 06/12/2013

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This page was last updated: June 18, 2013

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