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
The antiepileptic drug which does not produce enzyme induction is - 
Select and explain. 
A. Phenobarbitone, B. Sodium valproate, C. Phenytoin, D. Primidone
B: Sodium valproate
Answer: B: Sodium valproate 
Explanation: Ans. is 'b' i.e., Sodium valproate o Most of the anticonvulsants are enzyme inducers except valproate which is an inhibitor. Note : Valprate is an enzyme inhibitor overall but it induces metabolism of carbamazepine: "Valproate and carbamazepine induce each other;s metabolism"