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: Surgery
[{'content': 'Antiepileptic effect of phenytoin is increased by all of the following except: \nSelect and explain. \nA. Isoniazid, B. Sucralfate, C. Cimetidine, D. Warfarin', 'role': 'user'}, {'content': "Answer: B \nExplanation: Sucralfate INTERACTIONS Phenobarbitone competitively inhibits phenytoin metabolism, while by enzyme induction both enhance each other's degradation. Cabamazepine and phenytoin increases each other's metabolism. * Valproate displaces protein bound phenytoin and decreases its metabolism: plasma level of unbound phenytoin Increases. * Chloramphenicol, isoniazid, cimetidine, dicumarol and warfarin inhibit phenytoin metabolism & can precipitate its toxicitiy. Phenytoin induces microsomal enzymes and increase degradation of steroids (failure of oral contraceptives), digitoxin, doxycycline, theophyline, * A number of acidic drugs displace it from protein binding sites but this also enhances phenytoin clearance - concentration of free form does not change much. * Sucralfate binds phenytoin in g.i. tract and decreases its absorption.", 'role': 'assistant'}]