An alcoholic takes disulfiram and then consumes beer. Within minutes he develops flushing, throbbing headache, palpitations, nausea and hypotension. Disulfiram produces this reaction through inhibition of which enzyme, causing accumulation of which metabolite?
- A Alcohol dehydrogenase, ethanol
- B Aldehyde dehydrogenase, acetaldehyde ✓
- C Aldehyde dehydrogenase, acetate
- D Catalase, formaldehyde
Correct answer: B. Aldehyde dehydrogenase, acetaldehyde
Explanation
Ethanol is oxidised by alcohol dehydrogenase to acetaldehyde, which is normally cleared by mitochondrial aldehyde dehydrogenase (ALDH2) to acetate. Disulfiram irreversibly inhibits ALDH2, so acetaldehyde accumulates and produces flushing, headache, tachycardia, nausea and hypotension. Ethanol itself is not accumulated, acetate is the downstream product, and catalase is a minor oxidative pathway irrelevant here.
Reference: Katzung's Basic and Clinical Pharmacology, 15th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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