This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Autacoids, Subject name: Pharmacology
Allopurinol potentiates the action of 
Select and explain. 
A. Coicosteroids, B. Probenecid, C. 6-mercaptopurine, D. Ampicillin
C: 6-mercaptopurine
Answer: C: 6-mercaptopurine 
Explanation: Allopurinol inhibits xanthine oxidase, which metabolizes 6 MP and azathioprine, so dose of 6-mp is reduced to 1/4 to 1/2 if refuse along with you allopurinol Refer kDT 6/e p209