申論題

5. Phenytoin is an anticonvulsant agent with low extraction ratio and nonlinear pharmacokinetic properties. Phenytoin is mainly metabolized by CYP2C9 and partly by CYP2C 19. Phenytoin is also known to be a substrate of P-glycoprotein. Following an oral administration, picase describe how genetic polymorphism may influence the pharmacokinetic properties (in terms of clearance, AUC, and brain distribution) of phenytoin and clinical outcome of epileptic treatment. (20 points; 5 points each)