Phendimetrazine
A sympathomimetic anorectic prescribed for short-term management of obesity. It acts largely as a prodrug for phenmetrazine, releasing noradrenaline to suppress appetite. Indicated only for short courses because of tolerance, cardiovascular effects and dependence potential.
01 Overview
Phendimetrazine is a Schedule III anorectic used as a short-term adjunct to diet in obesity. It is substantially metabolised to phenmetrazine, an older, more potent stimulant, which accounts for much of its activity.
Like other anorectics, it produces modest short-term weight loss and is limited to brief courses because efficacy declines with tolerance and dependence can develop. Cardiovascular stimulation, insomnia and dry mouth are typical. It is contraindicated in significant cardiovascular disease and with MAO inhibitors.
02 Mechanism
Acts mainly as a prodrug for phenmetrazine, promoting noradrenaline release in the hypothalamus to suppress appetite.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Therapeutic (immediate-release) | 105–210 mg/day | Oral | 35 mg two-to-three times daily before meals; sustained-release 105 mg once 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 with CNS stimulation. | Mild | Common | Clinical | |
| Cardiovascular stimulationRaised heart rate and blood pressure; palpitations possible. | Moderate | Common | Clinical | |
| Tolerance and dependenceEfficacy declines with continued use and dependence can develop. | Moderate | Uncommon | Clinical |