False statement regarding phenytoin is:-

Most of the drugs which follow zero order kinetics, do so at higher plasma concentration including phenytoin PHENYTOIN It is a non sedating oral antiepileptic drug. Fosphenytoin is a water soluble prodrug of phenytoin that can be administered parenterally (i.v. or i.m.) for acute attack of seizures (status epilepticus). Fosphenytoincauses hyperphosphatemia in renal failure . ECG monitoring is must while administering fosphenytoin intravenously due to cardiotoxic effect . These drugs act by blocking the use dependent Na+ channels. Phenytoin is useful in GTCS and paial seizures. It can also be used as an anti-arrhythmic drug (class Ib) for the treatment of digitalis induced arrhythmia. This drug follows saturation kinetics (kinetics changes from first order to zero order at high doses, within therapeutic concentrations). Phenytoin from different manufacturers (different brands) have different bioavailability and therefore brand change can lead to toxicity or suboptimal levels. It is also a potent enzyme inducer and can increase the metabolism of various drugs.