The effect of repeated administration of diftalone on enzyme induction.

Plasma concentrations of diftalone have been examined in normal volunteers after a single dose (500 mg) and after 500 mg doses given twice daily for one week. An increase in post dosing urinary excretion of D-glucaric acid showed a correlation with the ratio of calculated to observed areas under the plasma concentration, time curve following the final dose in the multiple dosing studies, indicating that hepatic microsomal enzymes are induced after repeated administration of the drug. Single dose studies in the presence of aluminium hydroxide and sodium bicarbonate showed that the antacids had no significant effect on the absorption of diftalone.