P. Valodia et al., BENEFITS OF A CLINICAL PHARMACOKINETIC SERVICE IN OPTIMIZING PHENYTOIN USE IN THE WESTERN CAPE, South African medical journal, 88(7), 1998, pp. 873-875
Objectives. To study the benefits of a clinical pharmacokinetic servic
e in optimising phenytoin use in the Western Cape. Design;Assessment o
f the response to treatment was based on the number of seizures during
the 3 months before entering the study (first baseline period), 3 mon
ths after entering the study (second baseline period) and 3 months bef
ore the termination of the study (test period).. Patients kept a seizu
re diary throughout the study. The Michaelis-Menten model was used to
calculate doses and predict steady-state serum concentrations. Setting
.Nine epilepsy clinics. Subjects.One hundred and ninety-five (113 blac
k and 82 coloured) compliant people with epilepsy receiving generic ph
enytoin monotherapy. Outcome measures. Reduction in seizure frequency
and adverse effects. Results. A reduction in seizure frequency (64.8%
compared with ere-optimisation) was experienced by 64.9% of patients.
Mean seizure frequency was reduced from 3.39 to 1.18 per month. Reduct
ions in seizure frequency of 100% and more than 50% were reported by 3
9.2% 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 pharmacokinetic dosing service for phenytoin
applied in this study contributed significantly to the success of epi
lepsy management.