Benzphetamine

— THERAPEUTIC CATEGORIES —
  • Obesity
PAGE CONTENTS
  • Jump to Section
  • Generic Name & Formulations
  • Indications
  • Dosage and Administration
  • Contraindications
  • Boxed Warnings
  • Warnings/Precautions
  • Pharmacokinetics
  • Interactions
  • Adverse Reactions
  • Clinical Trials
  • Note
  • Patient Counseling

    • Benzphetamine Generic Name & Formulations

    Legal Class

    CIII

    General Description

    Benzphetamine HCl 50mg; scored tabs.

    Pharmacological Class

    Sympathomimetic.

    How Supplied

    Contact supplier

    Storage

    Store at 20° to 25°C with excursions permitted between 15° to 30°C (59° to 86°F).

    Manufacturer

    Various generic manufacturers

    Benzphetamine Indications

    Indications

    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.

    Benzphetamine Dosage and Administration

    Prior to Treatment Evaluations

    Baseline cardiac evaluation should be considered to detect pre-existing valvular heart diseases or pulmonary hypertension prior to initiation of benzphetamine treatment.

    Adult

    ≥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

    <17yrs: not recommended.

    Benzphetamine Contraindications

    Contraindications

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

    Benzphetamine Boxed Warnings

    Not Applicable

    Benzphetamine Warnings/Precautions

    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.

    Warnings/Precautions

    Pulmonary Hypertension (PH)

    • In a case-control epidemiological study, the use of anorectic agents was associated with an increased risk of developing pulmonary hypertension; benzphetamine was not specifically studied in this case-control study.
    • Treatment should be discontinued if patients report symptoms of PH (eg, unexplained dyspnea, angina, syncope, lower extremity pain); evaluate for possible pulmonary hypertension.
    • Baseline evaluation should be considered to detect pre-existing pulmonary hypertension.

    Valvular Heart Disease

    • Cardiac valvular disease has been reported in patients taking anoretic agents such as fenfluramine or dexfenfluramine.
    • No cases of this valvulopathy have been reported when benzphetamine has been used alone.
    • Baseline cardiac evaluation should be considered to detect pre-existing valvular heart diseases.
    • Not recommended in patients with known heart murmur or valvular heart disease.

    Development of Tolerance

    • Recommended dose should not be exceeded in an attempt to increase the effect.
    • Discontinue benzphetamine if tolerance develops.

    Risk of Dependence

    • Consider abuse potential when evaluating the desirability of including the drug as part of a weight reduction program.

    Hypertension/CVD

    • Not recommended for severely hypertensive patients or for patients with symptomatic cardiovascular disease including arrhythmias.
    • Use caution in patients with mild hypertension.

    Pregnancy Considerations

    Benzphetamine is contraindicated in pregnancy.

    Nursing Mother Considerations

    Amphetamines are excreted in human milk. Mothers taking amphetamines should be advised to refrain from nursing.

    Pediatric Considerations

    Safety and effectiveness in pediatric patients have not been established. The use of benzphetamine is not recommended in patients less than 17 years of age.

    Geriatric Considerations

    In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range. Studies did not include a sufficient number of patients aged 65 years and older.

    Benzphetamine Pharmacokinetics

    Metabolism

    Hepatic.

    Elimination

    Renal. Half-life: 4–5 hours.

    Benzphetamine Interactions

    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.

    Benzphetamine Adverse Reactions

    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).

    Benzphetamine Clinical Trials

    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.

    Benzphetamine Note

    Notes

    Formerly known under the brand name Didrex.

    Benzphetamine Patient Counseling

    Patient Counseling

    Patients should be cautioned about concomitant use of alcohol or other CNS-active drugs and benzphetamine.

    Patients should be advised to observe caution when driving or engaging in any potentially hazardous activity.

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