Autonomic
Drugs that turn the parasympathetic "rest-and-digest" system up (cholinergics) or down (anticholinergics) — mirror-image classes anchored by atropine, the bradycardia and organophosphate antidote — plus the α-adrenergic antagonists, which release the sympathetic α squeeze in pheochromocytoma and benign prostatic hyperplasia.
Cholinergic Agonists
High-yieldTurn UP “rest-and-digest.” Used for urinary retention, myasthenia, dry mouth and the eye; methacholine tests airway reactivity and physostigmine reverses anticholinergic poisoning. Overdose = cholinergic crisis (SLUDGE).
Anticholinergics (Atropine)
High-yieldBlock "rest-and-digest." Atropine treats bradycardia; glycopyrrolate dries secretions with fewer CNS effects; tropicamide and cyclopentolate drops dilate pupils; classic toxidrome — can’t see/pee/spit/poop.
Alpha-Adrenergic Antagonists (α-Blockers)
High-yieldRelease the sympathetic α squeeze. Nonselective phentolamine and phenoxybenzamine control pheochromocytoma; uroselective tamsulosin, alfuzosin and silodosin ease BPH. Metyrosine cuts catecholamine synthesis instead. Watch for orthostatic hypotension.