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: Anaesthesia
Which of the following anaesthetic drugs is contraindicated in chronic renal failure – 
Select and explain. 
A. Morphine, B. Fentanyl, C. Pethidine, D. Atracurium
C: Pethidine
Answer: C: Pethidine 
Explanation: Pethidine (Meperidine) is metabolized to form normeperidine (long half life) which is excreted by the kidney. Administration of pethidine to a patient with Chronic Renal Failure causes toxic accumulation of this metabo­lite and is hence contraindicated.