This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Chemotherapy: General Principles, Subject name: Pharmacology
Allopurinol potentiates action of: 
Select and explain. 
A. Azathioprine, B. Busulfan, C. Actinomycin, D. Procarbazine
A: Azathioprine
Answer: A: Azathioprine 
Explanation: Ans. (A) Azathioprine(Ref: KDT 8th/e p922)Allopurinol inhibits degradation of azathioprine and 6-mercaptopurine and thus potentiates their action.