<prompt> CYP-450 inducers are -CimetidineKetoconazolePhenobarbitoneAll  <response>: Ans. is c i.e., Phenobarbitone Drugs that induce microsomal enzymes o Phenobarbitone o Rifampin o Isoniazid o Phenylbutazone o DDT o Carbamezepine o Clofibrate o Ritonavir o Chronic alcohol intake o Cyclophosphamide o Phenytoin o Glucocoicoids o Chloral hydrate o Griseofulvin o Omeprazole o Meprobamate o Glutethimide o Cigarette smoking Remember o All Barbiturates are enzyme inducers except secobarbital, which inhibits the enzyme. o Acutely, ritonavir is an inhibitor, while with chronic repeated administration it acts as an inducer. 