Phendimetrazine Tartrate

  • Obesity

Phendimetrazine Tartrate Generic Name & Formulations

General Description

Phendimetrazine tartrate 35mg; scored tabs.

Pharmacological Class


How Supplied

Contact supplier.


Store at 20° to 25° C (68° to 77° F). 

Protect from moisture.

Phendimetrazine Tartrate Indications


Short-term adjunct in managing exogenous obesity.


Phendimetrazine tartrate tablets are indicated in the management of exogenous obesity as a short term adjunct (a few weeks) in a regimen of weight reduction based on caloric restriction.

Phendimetrazine Tartrate Dosage and Administration


35mg 2 or 3 times daily, 1 hour before meals; may reduce to 17.5mg/dose. Max 210mg/day in 3 evenly divided doses.


Usually 1 tablet (35 mg) 2 or 3 times daily, 1 hour before meals.

Dosage should be individualized to obtain an adequate response with the lowest effective dosage. In some cases 1/2 tablet (17.5 mg) per dose may be adequate. 

Dosage should not exceed 2 tablets 3 times daily.


<12yrs: not recommended.

Phendimetrazine Tartrate Contraindications


Advanced arteriosclerosis. Cardiovascular disease. Moderate or severe hypertension. Hyperthyroidism. Glaucoma. Highly nervous or agitated states. Drug or alcohol abuse. Concomitant CNS stimulants. During or within 14 days of MAOIs (see Interactions).

Phendimetrazine Tartrate Boxed Warnings

Not Applicable

Phendimetrazine Tartrate Warnings/Precautions


Discontinue after a few weeks as tolerance to anorectic effect occurs. Avoid abrupt cessation after prolonged high doses. Mild hypertension. Abuse and dependence potential. Diabetes. Reevaluate after drug-free interval. Prescribe minimal supply to avoid overdose. Pregnancy.


Discontinue therapy if tolerance to the anorectic effect of phendimetrazine develops within a few weeks. The maximum recommended dose should not be exceeded.

Abrupt cessation of administration following prolonged high dosage results in extreme fatigue and depression. Because of the effect on the central nervous system, phendimetrazine may impair the ability of the patient to engage in potentially hazardous activities such as operating machinery or driving a motor vehicle; the patient should therefore be cautioned accordingly.

Caution in prescribing phendimetrazine tartrate for patients with even mild hypertension.

Insulin requirements in diabetes mellitus may be altered in association with the use of phendimetrazine and the concomitant dietary regimen.

The least amount feasible should be prescribed or dispensed at one time in order to minimize the possibility of overdosage.

The phendimetrazine tartrate yellow tablets contain FD&C yellow No. 5 (tartrazine) which may cause allergic type reactions (including bronchial asthma) in certain susceptible individuals. Caution in patients who also have aspirin hypersensitivity.

Phendimetrazine tartrate is related chemically and pharmacologically to the amphetamines. Amphetamines and related stimulant drugs have been extensively abused and the possibility of abuse of phendimetrazine should be kept in mind when evaluating the desirability of including a drug as part of a weight reduction program. Abuse of amphetamines and related drugs may be associated with intense psychological dependence and severe social dysfunction. There are reports of patients who have increased the dosage to many times that recommended. Manifestations of chronic intoxication with anorectic drugs include severe dermatoses, marked insomnia, irritability, hyperactivity and personality changes. The most severe manifestation of chronic intoxications is psychosis, often clinically indistinguishable from schizophrenia.

Pregnancy Considerations

Safe use in pregnancy has not been established. 

Until more information is available, phendimetrazine tartrate should not be taken by women who are or who may become pregnant unless the potential benefits outweigh the possible hazards.

Pediatric Considerations

Phendimetrazine tartrate is not recommended for use in children under 12 years of age.

Phendimetrazine Tartrate Pharmacokinetics


The major route of elimination is via the kidneys where most of the drug and metabolites are excreted. Some of the drug is metabolized to phenmetrazine and also phendimetrazine-N-oxide.

The average half-life of elimination is about 3.7 hours for both the extended-release and immediate release forms. 

Phendimetrazine Tartrate Interactions


Hypertensive crisis with MAOIs. May antagonize guanethidine. CNS effects with alcohol, other CNS drugs.


Concomitant use of phendimetrazine tartrate within 14 days after the administration of monoamine oxidase inhibitors may result in a hypertensive crisis.

Phendimetrazine may decrease the hypotensive effect of guanethidine.

Phendimetrazine Tartrate Adverse Reactions

Adverse Reactions

Palpitation, tachycardia, hypertension, CNS overstimulation, dry mouth, GI disturbances, urinary frequency, changes in libido.

Adverse Reactions

Cardiovascular: Palpitation, tachycardia, elevated blood pressure.

Central Nervous System: Overstimulation, restlessness, insomnia, agitation, flushing, tremor, sweating, dizziness, headache, psychotic state, blurring of vision.

Gastrointestinal: Dryness of the mouth, nausea, diarrhea, constipation, stomach pain.

Genitourinary: Urinary frequency, dysuria, changes in libido.

Phendimetrazine Tartrate Clinical Trials

See Literature

Phendimetrazine Tartrate Note


Formerly known under the brand name Bontril PDM.

Phendimetrazine Tartrate Patient Counseling

See Literature