Indications for: Benzphetamine

Management of exogenous obesity as a short term (a few weeks) adjunct in a regimen of weight reduction based on caloric restriction in patients with an initial body mass index (BMI) of 30 kg/m2 or higher who have not responded to appropriate weight reducing regimen (diet and/or exercise) alone.

Clinical Trials:

Adult obese patients instructed in dietary management and treated with anorectic drugs lose more weight on average than those receiving placebo and diet, as determined in relatively short-term clinical trials.

The magnitude of increased weight loss of drug-treated patients over placebo patients is only a fraction of a pound a week. The rate of weight loss is greatest in the first weeks of therapy for both drug and placebo patients and tends to decrease in succeeding weeks.

The total impact of drug-induced weight loss over that of diet alone must be considered clinically limited.

Adult Dosage:

≥17yrs: Individualized. Initially 25–50mg once daily in mid-morning or mid-afternoon. Increase if needed to 25–50mg 1–3 times daily. Continue treatment only if patient has satisfactory weight loss within the first 4 weeks of treatment (eg, weight loss of at least 4lbs, or as determined by the physician and patient).

Children Dosage:

<17yrs: not recommended.

Benzphetamine Contraindications:

Advanced arteriosclerosis. Cardiovascular disease. Hypertension. Hyperthyroidism. Agitation. Drug or alcohol abuse. During or within 14 days of MAOIs. Pregnancy.

Benzphetamine Warnings/Precautions:

See Contraindications. Risk of pulmonary hypertension, valvular heart disease. Discontinue if new, unexplained dyspnea, angina, syncope, or lower extremity edema develops. Discontinue if tolerance to the anorectant effect develops. Mild hypertension. Diabetes. Prescribe minimal supply to avoid overdose.  Elderly.

Benzphetamine Classification:


Benzphetamine Interactions:

Contraindicated with MAOIs as hypertensive crisis may result. Should not be used in combination with other anorectic agents; potential for serious cardiac problems. Adverse interactions with alcohol should be considered. Do not use concomitantly with other CNS stimulants. Antidiabetic drug requirements (eg, insulin) may be altered. May decrease the hypotensive effect of antihypertensives. May enhance the effects of tricyclic antidepressants. Urinary alkalinizing agents increase blood levels and decrease excretion of amphetamines. Urinary acidifying agents decrease blood levels and increase excretion of amphetamines.

Adverse Reactions:

Palpitation, tachycardia, BP elevation, overstimulation, restlessness, dizziness, insomnia, tremor, sweating, headache, dry mouth, unpleasant taste, nausea, diarrhea, other GI disturbances, urticaria and other allergic reactions involving the skin, changes in libido, withdrawal effects (following prolonged high dosage administration).


Formerly known under the brand name Didrex.



Drug Elimination:

Renal. Half-life: 4–5 hours.

How Supplied:

Contact supplier