Phendimetrazine Tartrate

Pronunciation

Pronunciation: fen-dye-ME-tra-zeen TAR-trate
Class: Anorexiant

Trade Names

Bontril PDM
- Tablets 35 mg

Bontril Slow-Release
- Tablets 35 mg

Melfiat-105 Unicelles
- Tablets 35 mg

Prelu-2
- Capsules, sustained-release 105 mg

Pharmacology

May stimulate satiety center in brain, causing appetite suppression.

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Pharmacokinetics

Absorption

Phendimetrazine is readily absorbed.

Metabolism

Phendimetrazine metabolism is hepatic. Some of the drug is metabolized to phenmetrazine and phendimetrazine-N-oxide.

Elimination

Excretion is via the kidneys and is increased by acidifying the urine. The t ½ is 1.9 h (immediate-release) and 9.8 h (slow-release).

Duration

4 hr.

Indications and Usage

Short-term (few weeks) adjunct to diet plan to reduce weight.

Contraindications

Hypersensitivity to sympathomimetic amines; pregnancy; advanced arteriosclerosis; symptomatic CV disease; moderate to severe hypertension; hyperthyroidism; glaucoma; agitated states; history of drug abuse; during or within 14 days following the administration of an MAOI.

Dosage and Administration

Adults and children (12 yr of age or older)

PO Tablets or capsules: 35 mg 2 or 3 times daily before meals; sustained-release capsules: 105 mg once daily in the morning before breakfast.

General Advice

Swallow sustained-release capsule whole. Do not crush, chew, or open capsule.

Storage/Stability

Store at controlled room temperature (59° to 86°F).

Drug Interactions

Guanethidine

May decrease hypotensive effect of guanethidine.

MAOIs (eg, phenelzine); furazolidone

May cause hypertensive crisis and intracranial hemorrhage.

Selective serotonin reuptake inhibitors (eg, fluoxetine)

Sympathomimetic effects of phendimetrazine and risk of “serotonin syndrome” may be increased.

Laboratory Test Interactions

None well documented.

Adverse Reactions

Cardiovascular

Palpitation; tachycardia, hypertension.

CNS

Overstimulation; restlessness; dizziness; insomnia; euphoria; dysphoria; tremor; headache; psychosis.

Dermatologic

Allergic urticaria.

GI

Dry mouth; unpleasant taste; diarrhea; constipation.

Genitourinary

Impotence; changes in libido.

Precautions

Pregnancy

Do not use in women who are pregnant or may become pregnant.

Lactation

Undetermined.

Children

Safety and efficacy not established in children younger than 12 yr of age.

Special Risk Patients

Use with caution in patients with glaucoma, hypertension, diabetes mellitus.

Drug dependence

Psychological and physical dependence may occur with continued use; this class of drugs has been extensively abused.

Tolerance

Tolerance to the anorectic effect usually develops within a few weeks.

Overdosage

Symptoms

Restlessness, tremor, hyperreflexia, rapid respiration, confusion, assaultiveness, hallucinations, panic states, fatigue, depression, arrhythmias, hypertension, hypotension, circulatory collapse, nausea, vomiting, diarrhea, abdominal cramps, convulsions, coma, death.

Patient Information

  • Advise patient using immediate-release tablet to take prescribed dose 1 h before meals and to take last dose several hours before bedtime.
  • Advise patient using sustained-release capsule that medication is slowly released over 12 h and to take dose in the morning. Advise patient to swallow the capsule whole and to not crush or chew the capsule.
  • Encourage patient to follow medically supervised weight reduction program. Emphasize that this medication will only work in conjunction with a caloric restricted diet and exercise program.
  • Advise patient that medication should be taken as prescribed and to not stop taking or change the dose unless advised to do so by the health care provider.
  • Explain that appetite suppressant effects are temporary and tolerance to medication and dependence can occur. Caution patient not to increase the dose in an effort to overcome the tolerance when it occurs.
  • Remind diabetic patient to monitor blood sugar more frequently while implementing dietary restrictions and to notify health care provider if significant changes in blood sugar occur.
  • Caution patient that drug may impair the ability to drive or perform other tasks requiring mental alertness.
  • Advise patient to notify health care provider immediately if the following symptoms occur: chest pain, palpitations, nervousness, dizziness.
  • Advise patient to notify health care provider if experiencing any unusual or unexplained symptoms.

Copyright © 2009 Wolters Kluwer Health.

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