Changes in serum triglyceride and cholesterol levels during long-term phenytoin treatment for epilepsy.

The effect of long-term phenytoin therapy on serum triglyceride and cholesterol levels in 20 patients with epilepsy was investigated. In patients followed up for six years, phenytoin treatment was associated with an increase in serum triglyceride and cholesterol levels. The most significant increases in lipid levels were measured during the first months of therapy, whereafter values generally tended to decrease. The elevation in serum triglyceride concentration was relatively greater than that in serum cholesterol level. Cholesterol concentrations, however, remained high for a longer period. The results demonstrate that phenytoin therapy for epilepsy is associated with a rise in serum triglyceride and cholesterol levels, the degree of which seems to be related to the duration of the treatment. The changes presumably reflect phenytoin effects on hepatic lipid metabolism.