PHARMACOKINETICS OF PHENYTOIN IN ROUTINE CLINIC PATIENTS IN MALAYSIA

We estimated individual and population Michaelis-Menten pharmacokineti c parameters for phenytoin (DPH) in epileptic patients attending our n eurology clinic using the computer programme. OPT(R). Our results agre ed well with literature values but were lower than those we obtained e arlier in a smaller number of patients. The K(m) was independent of ag e, weight and sex but there was a weak, correlation between V(m) and b ody weight. We conclude that the use of population V(m) and K(m) in no rmograms could lead to errors in DPH dose estimations as they correlat ed very poorly with patient characteristics. OPT(R) was easy to use an d sufficiently accurate for deriving dose estimates in routine patient s. Its use would enable practitioners to generate their patients' own parameters for use in individual dosage adjustments. The estimates can subsequently be updated as more data become available.