Vinpocetine therapy does not change imipramine pharmacokinetics in man

The influence of vinpocetine on imipramine steady-state plasma levels was investigated in 18 healthy volunteers. Twenty-five mg imipramine were given t.i.d. for a total of 21 days, vinpocetine treatment was started on day 11 with 10 mg t.i.d. and continued until the end of the study. The AUC of imipramine plasma levels were obtained using consecutive imipramine plasma level determinations from samples drawn every 2 h from 8:00 a.m. to 8:00 p.m. by trapezoidal rule. AUCs of day 10 without and of day 21 during concomitant vinpocetine treatment were compared, demonstrating the independence of imipramine's bioavailability from concomitant vinpocetine treatment. There were no indications to assume a changed absorption of imipramine due to vinpocetine as would be reflected in Cmax and tmax values. Imipramine metabolization to the still effective metabolite desipramine shows a huge interindividual variability although it remains constant for the individual. The analysis of this parameter in the course of this study does not suggest that it is changed due to vinpocetine treatment.