Clinical studies on the vasodilating and anti-platelet effects of OP-41483, a prostacyclin derivative.

The vasodilating and anti-platelet actions of OP-41483 was studied to determine the effective dose of this drug for the treatment of ischemic lower limbs. The compound was given to 11 patients intravenously at rates of 2.5, 5.0 and 10.0 ng/kg/min. Infusion at a rate of 10 ng/kg/min increased the mean flow rate of the tibial arteries from 3.15 +/- 1.77 ml/min before the infusion, to 7.89 +/- 2.51 ml/min (p less than 0.001) and to 6.38 +/- 3.19 ml/min (p less than 0.001), at the time of, and 60 minutes after the cessation of the infusion, respectively. The peripheral flow resistance of the tibial arteries was reduced from 2.1 +/- 1.12 X 10(5) dyne.sec/cm5 before the infusion to 0.9 +/- 0.33 X 10(5) dyne.sec/cm5 (p less than 0.001) and to 1.2 +/- 0.78 X 10(5) dyne.sec/cm5 (p less than 0.05), at the time of, and 60 minutes after the cessation of the infusion. ADP-induced platelet aggregation was reduced from 73.3 +/- 17.6% before the infusion to 50.7 +/- 24.5% (p less than 0.01) and to 64.0 +/- 23.5% (p less than 0.05), at the time of, and 60 minutes after the cessation of the infusion, respectively. Collagen-induced platelet aggregation was also reduced from 71.4 +/- 24.0% to 66.6 +/- 21.5% before and after the infusion (p less than 0.05).