Learning Objective
Identify medications that cause multiorgan adverse drug reactions, with emphasis on antimuscarinic toxicity and disulfiram-like reactions, and recognize their characteristic clinical features.
Key Drug Reactions
| Drug Reaction | Causal Agents | Clinical Notes |
|---|---|---|
| Antimuscarinic toxicity | Atropine, tricyclic antidepressants (TCAs), first-generation H1 antihistamines, antipsychotics | Presents with dry skin, dry mouth, mydriasis, urinary retention, constipation, tachycardia, and delirium (“hot as a hare, dry as a bone, blind as a bat, mad as a hatter”) |
| Disulfiram-like reaction | First-generation sulfonylureas, procarbazine, certain cephalosporins (eg, cefotetan), griseofulvin, metronidazole | Alcohol ingestion causes flushing, nausea, vomiting, headache, and hypotension due to acetaldehyde accumulation |
High-Yield Exam Pearl
- Metronidazole + alcohol → disulfiram-like reaction
- TCAs → antimuscarinic toxicity + cardiac conduction abnormalities
