LACK OF PHARMACOKINETIC INTERACTION BETWEEN THE SELECTIVE DOPAMINE AGONIST CABERGOLINE AND THE MAO-B INHIBITOR SELEGILINE

The addition of a dopamine agonist and of a monoamine oxidase type B i nhibitor to 1-dopa has been suggested in the therapy of Parkinson's di sease. The plasma pharmacokinetics of both cabergoline and 1-dopa have previously been shown to remain unaffected when the two drugs are giv en concomitant ly. This study aimed at examining whether the plasma ph armacokinetic parameters of cabergoline and selegiline are modified wh en given in combination. Selegiline is hardly detectable in plasma. Th erefore, the plasma levels of its metabolites amphetamine, methampheta mine and desmetylselegiline were used to assess the effect of cabergol ine co-administration. Plasma levels of the selegiline metabolites wer e determined first after selegiline administration (10 mg/day) for 8 d ays, and then after administration of both drugs for 22 additional day s (day 30). Cabergoline plasma levels were measured on day 30, and the n after administration of cabergoline (1 mg/day) alone for further 22 days. No statistical difference was found between the C-max,C-ss, t(ma x,ss), AUC(0-24)h(,ss), C-0h,C-ss, C-24h,C-ss values of cabergoline an d of the selegiline metabolites when the two drugs were given alone or in combination, indicating the absence of pharmacokinetic interaction between cabergoline and selegiline.