Correct Answer: C. Flushing, vomiting, and dizziness
Rationale: Disulfiram inhibits aldehyde dehydrogenase, blocking ethanol metabolism at the acetaldehyde stage. Acetaldehyde accumulation causes severe facial flushing, throbbing headache, nausea, violent vomiting, diaphoresis, dyspnea, hypotension, and dizziness.
- Option A is incorrect: Isolated cramps and diarrhea are characteristic of opioid withdrawal, not the classic acetaldehyde reaction.
- Option B is incorrect: Drowsiness and respiratory depression reflect sedative-hypnotic overdose, not disulfiram ethanol toxicity.
- Option D is incorrect: While tachycardia occurs, blood pressure characteristically drops (hypotension/vasodilation), which can lead to shock in severe reactions.