An assessment of the contribution of clonidine metabolised from alinidine to the cardiovascular effects of alinidine.

摘要

Five healthy volunteers (mean age 20.6 years, mean weight 71 kg) received in random order on day 1 and day 8 a single dose of alinidine 40 mg, clonidine 0.1 mg or placebo and on days 2-7 alinidine 40 mg, clonidine 0.1 mg or placebo given three times a day with 1 week between treatment periods. Blood samples were taken for measurement of concentrations of alinidine and clonidine during alinidine administration and of clonidine during clonidine dosing. Heart rate and blood pressure were recorded in supine and standing positions and heart rate after 3 min exercise. Plasma concentrations of alinidine reached a maximum of 163.6 +/- 10.0 ng/ml 2 h after alinidine administration on day 1 and during chronic administration similar concentrations were achieved. Clonidine plasma concentrations reached 0.3 +/- 0.11 ng/ml 6 h after alinidine 40 mg on day 1, and during chronic administration of alinidine, increased to a steady state on day 5 with trough and 2 h values of 0.73 +/- 0.15 and 0.86 +/- 0.14 ng/ml respectively. After the first dose of clonidine on day 1, the maximum plasma concentration of clonidine was 0.32 +/- 0.1 ng/ml at 4 h, during chronic administration clonidine plasma concentration rose to 1.04 +/- 0.14 ng/ml 2 h after a dose on day 5. Alinidine produced a greater reduction in the exercise tachycardia than clonidine.(ABSTRACT TRUNCATED AT 250 WORDS)