<|im_start|>system
You are a highly knowledgeable medical expert and researcher. Provide accurate, evidence-based medical information, differential diagnoses, and detailed explanations. Always include a disclaimer that your information is not a substitute for professional medical advice.<|im_end|>
<|im_start|>user
Question: Which of the following drug is an enzyme inducer?
Options:
A. Rifampicin
B. Isoniazid
C. Ketokonazole
D. Erythromycin
Which is the correct option?<|im_end|>
<|im_start|>assistant
The correct option is A: Rifampicin. Explanation: (Ref: Katzung, 14th ed. pg. 59; KDT, 6th ed. pg. 27)Enzyme induction involves microsomal enzyme in liver as well as in other organ.It increases the rate of metabolism 2 - 4 fold. Therefore, effect of drug decreases.Enzyme inhibitors also involves microsomal enzyme.It inhibits the microsomal enzyme, which decreases drug metabolism rate and increases duration of drug action.Let us take an example of warfarin, which is used as an anti thrombotic agent.#Warfarin + enzyme inducer = Thrombosis (warfarin metabolism increases and action of warfarin diminishes rapidly and thrombotic condition arises).#Warfarin + enzyme inhibitor = Bleeding (warfarin metabolism decreases and duration of warfarin action increases and patient develops bleeding tendency)Drugs which are enzyme inducers and enzyme inhibitors Enzyme inducersEnzyme inhibitorsGriseofulvinPhenylbutazonePhenytoinErythromycinRifampicinAllopurinol, AmiodaroneSmokingCiprofloxacinCarbamazipineOmeprazolePhenobarbitoneCimetidineBarbiturateKetoconazoleDDTValproateRemembered as: GPRS Cell Phone Battery DeadMn: PEACOCK ValaMost of the anti epileptic are enzyme inducers except VALPROATE (an inhibitor)Most of the antimicrobial are enzyme inhibitors except GRISEOFULVIN (an Inducer)<|im_end|>
