Antipyrine clearance and alpha 1-acid glycoprotein levels after isotretinoin.

Eight male subjects aged 18-24 years were treated with 0.5 mg of isotretinoin day-1 kg-1. After 4 weeks levels of cholesterol (P less than 0.05) and triglyceride (P less than 0.05) were increased and levels of high-density lipoprotein (HDL)-cholesterol were decreased (P less than 0.05). Concentrations of aspartate aminotransferase (P less than 0.01) and gamma-glutamyltranspeptidase (P less than 0.01) were higher after treatment; increased alkaline phosphatase and a reduction in bilirubin levels did not reach statistical significance. Values for thyroxine were reduced after isotretinoin and free thyroxine index was lower (P less than 0.01). Measurements of salivary clearance of antipyrine and levels of alpha 1-acid glycoprotein were lower after treatment but these differences did not reach statistical significance. The findings suggest that there is a small decrease in hepatic microsomal-enzyme activity after isotretinoin and that the unwanted effects on lipids, liver and thyroid function are unlikely to be due to hepatic microsomal-enzyme induction.