This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Kidney, Subject name: Medicine
Most impoant cause of interstitial nepliritis is - 
Select and explain. 
A. Drugs, B. Infection, C. Malignancy, D. Dehydration
A: Drugs
Answer: A: Drugs 
Explanation: Acute Interstitial nephritis is far more often encountered as an allergic reaction to drug. Drugs causing AIN - Antibiotics (sulfonamides, vancomycin, erythromycin, rifampin, ethambutol, acyclovir) NSAIDS Diuretics (rarely thiazides, loop diuretics, triamterene) Anticonvulsants(phenytoin,valproate,carbamazapine,phenobarbitol PPI'S Ref:Harrison 20 th edition pg no 2157