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Benzphetamine Dosage

The information at is not a substitute for medical advice. ALWAYS consult your doctor or pharmacist.

Usual Adult Dose for:

Additional dosage information:

Usual Adult Dose for Obesity

Initial dose: 25 to 50 mg orally once a day in the midmorning or midafternoon

Maintenance dose: 25 to 50 mg orally one to three times a day; dose or frequency should be individualized based on the patient's needs and response

A single daily dose is preferably given in midmorning or midafternoon, according to the patient's eating habits. It may be desirable to avoid late afternoon administration in some patients.

Renal Dose Adjustments

Data not available

Liver Dose Adjustments

Data not available


Benzphetamine is contraindicated in patients with advanced arteriosclerosis, symptomatic cardiovascular disease (including arrhythmias), moderate to severe hypertension, hyperthyroidism, glaucoma, or known hypersensitivity or idiosyncrasy to sympathomimetic amines. Caution should be exercised when prescribing amphetamines to patients with mild hypertension.

Benzphetamine should not be administered concurrently or within 14 days following use of monoamine oxidase inhibitors, since such use may result in hypertensive crisis. In addition, benzphetamine should not be used concomitantly with other CNS stimulants.

Benzphetamine may cause fetal harm and is contraindicated in women who are or may become pregnant. Any patient who becomes pregnant while taking benzphetamine should be apprised of the potential hazard to the fetus.

Benzphetamine should not be administered to agitated patients or patients with a history of drug abuse.

Benzphetamine is listed as a Schedule III drug under the Controlled Substances Act by the Drug Enforcement Agency. Amphetamines are subject to abuse, which may be associated with psychological dependence and severe social dysfunction. Abrupt cessation following prolonged exposure to high dosages can result in extreme fatigue and mental depression, as well as changes on the sleep EEG. In general, the smallest quantity feasible should be prescribed at any one time in order to minimize the possibility of overdosage.

Benzphetamine is not recommended for patients who used any anorectic agents within the prior year.

Benzphetamine should not be used in combination with other anorectic agents (including prescription, over-the-counter, and herbal products). Concomitant use has not been studied and may have the potential for serious cardiac problems.

The onset or aggravation of exertional dyspnea or unexplained symptoms of angina pectoris, syncope, or lower extremity edema suggest the possibility of pulmonary hypertension development. If such symptoms occur, benzphetamine should be discontinued at once, and the patient should be evaluated for pulmonary hypertension.

Valvular heart disease associated with the use of some anorectic agents such as fenfluramine and dexfenfluramine has been reported. Possible causal factors include extended duration of use, higher than recommended dosage, and/or concomitant use with other anorectics. No cases of this valvulopathy have been reported with benzphetamine monotherapy.

The potential risk of serious side effects (such as valvular heart disease and pulmonary hypertension) should be considered carefully against the potential benefit of weight loss. Baseline cardiac evaluation should be considered to detect preexisting valvular heart diseases or pulmonary hypertension prior to initiation of benzphetamine therapy. Benzphetamine is not recommended in patients with known heart murmur or valvular heart disease. Echocardiogram (during and after treatment) could help detect the occurrence of any valvular disorders. To limit unnecessary exposure and risks, treatment should be continued only if the patient has satisfactory weight loss within the first 4 weeks.

Tachyphylaxis and tolerance have been demonstrated with amphetamines. When tolerance to the anorectic effect of benzphetamine develops, the recommended dosage should not be exceeded in an attempt to increase the effect; rather, the drug should be discontinued.

Safety and efficacy have not been established in patients aged 65 years of age or older. Caution is advised when prescribing benzphetamine to patients over the age of 65. Because of the greater frequency of decreased hepatic, renal, and cardiac function, dosage selection for the elderly should start at the low end of the dosing range.

Safety and efficacy have not been established in pediatric patients. The use of benzphetamine in children under the age of 12 is not recommended.


Data not available