Abstract
Bioavailabilities of three different phenytoin (PHT) powders sold in Japan (companies S, D and F) were compared. One hundred and fifty children (aged 2-15 years) were assayed PHT plasma levels in steady state under the condition that PHT plasma level was 2.5-15.0μg/m/ and S/D was obtained (S plasma level of PHT μg/ml, D: dose of PHT mg/kg/day).
These children were divided into two groups by age (under 6 years old and over 7 years old) for each group. In the older age group, bioavailability was high in the order of S, D and F with a statistically significance. In the younger age group, S and D showed equal bioavailabilities but F showed a low bioavailability also statistically significant.
It was concluded that these differences may have been caused by the degree of smashing of PHT crystals.
Official organization should check the bioavailability of anticonvulsant produced by different drug companies and physicians should always pay attention to this problem.
