Phenytoin is a widely prescribed anticonvulsant drug. There is a wide interpatient as well as intrapatient variability in serumphenytoin levels despite standard doses. Phenytoin dosing is challenging because the drug exhibits nonlinear kinetics and interacts with a number of drugs. Children metabolize the drug faster as compared to adults. Ageing is also associated with progressive decline in phenytoin clearance. Many CYP450 enzymes show a sex-dependent difference in activity. The objective for this study was to find the effects of sex and ageing on serumphenytoin levels.
Methods:
The influence of sex and ageing on the serumphenytoin levels was evaluated retrospectively in 96 anonymized epileptic patientswho had received phenytoin alone for more than four weeks. These patients were divided into three age groups, up to 18 years (children), 19-60 years (adults) and more than 60 years (elderly).