Thalicarpine (NSC-68075): plasma decay and urinary excretion in man.

The plasma decay and urinary excretion of 3H-thalicarpine were studied in a total of 19 patients at doses of 300-1900 mg/m2. Plasma decay was triexponential with a terminal phase half-life of 198-1386 hours in five patients. Urinary excretion was slow and erratic, a total of 19.84% of the dose being excreted in 285 hours in nine patients. Only small amounts of unchanged thalicarpine appeared in the cerebrospinal fluid. The data indicate extensive localization of thalicarpine in the tissues and the danger of drug accumulation if it is given at short dose intervals.