Benzphetamine
A sympathomimetic anorectic (Didrex) used for short-term weight loss. It is metabolised to amphetamine and methamphetamine and suppresses appetite through central catecholamine release. Reserved for short courses given tolerance, cardiovascular effects and dependence potential.
01 Overview
Benzphetamine is a Schedule III anorectic indicated as a short-term adjunct to diet in obesity. It is metabolised in part to amphetamine and methamphetamine, which contribute to its central stimulant and anorectic effects.
As with other anorectics, weight loss is modest and the drug is limited to brief use because of declining efficacy and dependence potential. Cardiovascular stimulation, insomnia and dry mouth are typical, and it is contraindicated in significant cardiovascular disease and with MAO inhibitors.
02 Mechanism
Metabolised to amphetamine and methamphetamine, promoting release of noradrenaline and dopamine in the hypothalamus to suppress appetite.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Therapeutic (short-term weight loss) | 25–150 mg/day | Oral | Start 25-50 mg once daily, titrate to 25-50 mg one-to-three times daily. Short-term use. |
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Appetite suppression and weight lossReduces appetite as a short-term adjunct to diet in obesity. | Modest short-term weight loss | Clinical |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| InsomniaDifficulty sleeping from CNS stimulation. | Mild | Common | Clinical | |
| Cardiovascular stimulationRaised heart rate and blood pressure; palpitations. | Moderate | Common | Clinical | |
| Tolerance and dependenceEfficacy wanes and dependence can occur, hence short-term indication. | Moderate | Uncommon | Clinical |