This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Pharmacotherapy in psychiatry, Subject name: Psychiatry
Disulfiram acts by 
Select and explain. 
A. Inhibiting alcohol dehydrogenase, B. Inhibiting aldehyde dehydrogenase, C. Both 1 and 2, D. None of the above
B: Inhibiting aldehyde dehydrogenase
Answer: B: Inhibiting aldehyde dehydrogenase 
Explanation: DISULFIRAM is a DETERRANT which acts by blocking acetaldehyde dehydrogenase When acetaldehyde dehydrogenase is blocked there will be increased amount of acetaldehyde that acts on mast cells and results in release of histamine that in turn leads to allergic reaction. Thus when a patient on disulfiram takes alcohol there would be allergic reaction that prevents the patient from using the substance Ref.Kaplon and sadock, synopsis of psychiatry, 11 th edition, pg no. 624