[The influence of hyperlipidemia on pharmacokinetics of free phenytoin]

The problem of the effects of metabolic changes on drug pharmacokinetics is not yet sufficiently known. Phenytoin was used for the assessment of the effects of lipid profile disturbances on drug pharmacokinetics. Phenytoin is a lipophilic substance. It was shown that hyperlipidaemia changes phenytoin pharmacokinetics and the pattern of these changes depends on the type of hyperlipidaemia. In hypercholesterolaemia and in mixed hyperlipidaemia the blood level of free phenytoin was elevated. It should be remembered that hypercholesterolaemia and mixed hyperlipidaemia re conditions increasing the risk of phenytoin overdosage and this should be considered in establishing drug dosage.