mecamylamine

Mecamylamine is a synthetic, non-depolarizing ganglion blocker and a nicotinic acetylcholine receptor antagonist that was historically used to treat hypertension. It blocks nicotinic receptors at autonomic ganglia, reducing transmission in both sympathetic and parasympathetic pathways. The net effect is a decrease in peripheral vascular resistance and blood pressure, though it can provoke reflex tachycardia and impair bowel and bladder motility due to parasympathetic blockade.

Pharmacology and administration: mecaylamine is administered by mouth and has a prolonged duration of action reflecting its pharmacokinetic properties. Because it inhibits autonomic transmission at multiple sites, tolerability is limited by widespread adverse effects.

Medical use and status: Introduced in the 1950s as one of the first ganglion-blocking antihypertensives, mecamylamine’s use declined with the development of safer therapies and it is now rarely prescribed for hypertension. It remains of interest in pharmacology as a research tool and has been studied as a potential aid in smoking cessation, though it is not a routine therapy for nicotine dependence.

Side effects and precautions: adverse effects are primarily autonomic and include orthostatic dizziness or hypotension, headache, constipation or urinary retention, nausea, and sexual dysfunction. It should be used with caution in patients with cardiovascular disease or autonomic dysfunction, and monitoring of blood pressure and heart rate is advised when it is used.