A Toxic doses, zero order kinetics is seen in: (A) Pencillin, (B) Phenytoin, (C) Valproate, (D) Carbamazepine
Answer is B. Phenytoin follows nonlinear (or zero-order) kinetics at therapeutic concentrations, because the rate of metabolism is close to the maximum capacity of the enzymes involved Ref-KDT 6/e p31