Pharmacokinetics and pharmacodynamics of olprinone after cardiac surgery

Phosphodiesterase type III inhibitors are often delivered by continuous intravenous infusion without initial loading to prevent hypotension, i.e., by "slow induction". We evaluated the pharmacokinetics (PK) and pharmacodynamics (PD) of olprinone slow induction after open-heart surgery.

Olprinone was infused at a rate of 0.2 microg x kg(-1) x min(-1) in seven patients post operatively after elective cardiac surgery. Olprinone plasma concentration was determined by HPLC. PK parameters were calculated from concentrations at 90 and 180 minutes after start of infusion. PD data were analyzed by collected E(max) model using SAAMII PC programs.

Systemic vascular resistance index initially decreased about 20 ng/mL and then cardiac index increased. Initially, a vasodilating effect occurs and then inotropic effect follows. Systemic hypotension may induced by the different EC50 between inotropic and vasodilating action. Moreover, much vasodilating effect will be observed with olprinone than with milrinone, based on our previous data.

Olprinone slow induction is useful and safe for critically ill patients.