Health Guide

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

There may be other brand names for this medicine.

When This Medicine Should Not Be Used:

This medicine is not right for everyone. Do not use it if you had an allergic reaction to phendimetrazine, or if you also use any other stimulant or diet pill. Do not use this medicine if you are feeling agitated or if you have glaucoma, an overactive thyroid, or a history of heart and blood vessel disease (such as uncontrolled high blood pressure, arrhythmia, clogged arteries, heart failure, pulmonary hypertension, or stroke). Do not use this medicine if you are pregnant or breastfeeding.

How to Use This Medicine:

Capsule, Long Acting Capsule, Tablet

  • Your doctor will tell you how much medicine to use. Do not use more than directed. Carefully follow your doctor's instructions for a reduced-calorie diet plan and regular exercise.
  • Take the tablet 1 hour before a meal. Take the capsule 30 to 60 minutes before a meal.
  • Swallow the capsule whole. Do not break, crush, or chew it.
  • Missed dose: 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.
  • Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.

Drugs and Foods to Avoid:

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

  • Do not use this medicine if you have used an MAO inhibitor within the past 14 days.
  • Some medicines and foods can affect how phendimetrazine works. Tell your doctor if you are also using guanethidine, sibutramine, or insulin or diabetes medicine.

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.
  • Tell your doctor if you have kidney disease, diabetes, heart valve disease, or high blood pressure.
  • This medicine may cause a rare but serious condition called pulmonary hypertension.
  • Never use more than your prescribed dose. This medicine can be habit-forming. It is not meant for long-term use.
  • Do not stop using this medicine suddenly. Your doctor will need to slowly decrease your dose before you stop it completely.
  • This medicine may make you dizzy or drowsy. Do not drive or do anything else that could be dangerous until you know how this medicine affects you.
  • Keep all medicine out of the reach of children. Never share your medicine with anyone.

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
  • Fainting, swelling of your feet or lower legs
  • Fast, pounding, or uneven heartbeat

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
  • Sweating or flushing
  • Tremors or shaking

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: 7/4/2018
The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites.

All rights reserved