Benefits of a clinical pharmacokinetic service in optimising phenytoin use in the Western Cape
Objectives. To study the benefits of a clinical pharmacokinetic service in optimising phenytoin use in the Western Cape.
Design. Assessment of the response to treatment was based on the number of seizures during the 3 months before entering the study (first baseline period), 3 months after entering the study (second baseline period) and 3 months
before the termination of the study (test period). Patients kept a seizure diary throughout the study. The MichaelisMenten model was used to calculate doses and predict steady-state serum concentrations.
Setting. ine epilepsy clinics.
Subjects. One hundred and ninety-five (113 black and 82 coloured) compliant people with epilepsy receiving generic phenytoin monotherapy.
Outcome measures. Reduction in seizure frequency and adverse effects.
Results. A reduction in seizure frequency (64.8% compared with pre-optimisation) was experienced by 64.9% of patients. Mean seizure frequency was reduced from 3.39 to 1.18 per month. Reductions in seizure frequency of 100% and more
than 50% were reported by 39.2% and 58.7% of patients, respectively. Adverse effects of phenytoin were reduced from 20.5% at the first visit to 3.2% at the last visit.
Conclusion. The clinical pharrnacokinetic dosing service for phenytoin applied in this study contributed significantly to the success of epilepsy management.