<prompt> Which of the following statement about Phenytoin is true?It follows zero order kineticsIt is not teratogenicIt is excreted unchanged in urineIt does not induce microsomal enzymes  <response>: Phenytoin follows zero order kinetics at therapeutic plasma concentration. Other drugs following zero order kinetics are warfarin, alcohol, aspirin, theophylline, and tolbutamide. Phenytoin is a powerful microsomal enzyme inducer. Phenytoin is metabolized to inactive products by liver. Use of Phenytoin during pregnancy can cause Fetal hydantoin syndrome characterized by hypoplastic phalanges, cleft lip, cleft palate and microcephaly. It occurs due to a metabolite of phenytoin, arene oxide. REF: KATZUNG 14TH ED. 