Phenytoin dosage prediction

259 serum samples of 58 Saudi epileptic patients treated by Phenytoin as single therapy have been used to determine Vmax and Km of phenytoin and to study its dosage prediction. Bayesian feedback and Wagner methods have been compared with Michaelis - Menten linear transformation methods for prediction of phenytoin dosage. Hanes Woolf plot [s/v vs S] and Lineweaver - Burk [1/V vs 1/S] followed by Bayesian method are best for phenytoin dosage prediction. Wagner method and other Michaelis - Menten linear transformation methods resulted in higher errort