A 40-year-old chronic alcoholic is started on disulfiram therapy. What is the main pharmacological effect of this drug?

Correct option is B

Disulfiram inhibits aldehyde dehydrogenase, causing acetaldehyde accumulation if alcohol is taken → flushing, nausea, palpitations. This creates an aversion.
Explanation of options: (a) ✘ It actually blocks metabolism, doesn’t increase it. (b) ✔ Correct; disulfiram → unpleasant reaction with alcohol. (c) ✘ GABA agonism is mechanism of benzodiazepines, not disulfiram. (d) ✘ NMDA blockade is seen with acamprosate, not disulfiram.