Absorption, distribution and elimination of drotaverine.

14C-drotaverine [1(3',4'-diethoxybenzale)-6, 7-diethoxy-1, 2,3, 4-tetrahydroisoquinoline. HCl; No-SpaR] is well absorbed after subcutaneous and oral administration in mice. Its distribution is not specific. After intravenous administration the drug penetrates rapidly into every organ as indicated by whole body autoradiography. In the first hours the concentration of drotaverine was higher in the intestinal wall than in the other tissues. The concentrations of drotaverine in the organs decrease soon after administration and the drug is excreted mainly with the bile as beta-glucuronide; 60% of the dose was in the bile collected during 5 hours. During 96 hours of observation, 67% of the radioactivity administered was found in the stools while only 20% of it was eliminated with urine.