This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
Which of the following is least likely to cause interstitial nephritis on chronic use- 
Select and explain. 
A. Methicillin, B. Cephalothin, C. Heparin, D. Ampicillin
C: Heparin
Answer: C: Heparin 
Explanation: Ans. is 'c' i.e., Heparin Drug causing interstitial nephritis o Cephalosporine o Allopurinol o Phenindione o Thiazides o Rifampcin o Penicillins (esp. methicillin) o Ciprofloxacin o Sulphonamides o NSAIDS o Furosemide