Pimobendan was administered orally (10 mg single dose on day 1, then 5 mg twice daily for 4 weeks) to nine patients with chronic
heart failure undergoing hemodynamic monitoring. The time course of changes in plasma concentrations of
pimobendan and of its major active metabolite.
UD-CG 212 CL, was similar on days 1, 2, and 28.
Pimobendan plasma levels peaked 1.5-2.0 h after
drug intake: plasma concentrations of
UD-CG 212 CL reached a maximum 1 h later; the terminal half-life of
pimobendan in plasma varied between 1.44 +/- 0.94 h on day 1 and 1.19 +/- 0.36 h on day 2. Initially, cardiovascular variables changed with increasing plasma
drug levels and reached a maximum 4 h after
pimobendan intake; later, we found no correlation between plasma concentrations and hemodynamic effects. A steady state of hemodynamic improvement was achieved after 4 weeks of maintenance
therapy with
pimobendan. Baseline pulmonary capillary wedge pressure dropped from 16 +/- 7 mm Hg on day 1 to 5 +/- 3 mm Hg at noon on day 28 (-69%; p less than 0.001), and baseline cardiac index increased from 2.2 +/- 0.5 L/min/m2 on day 1 to 2.7 +/- 0.9 L/min/m2 on day 28 (+23%; p less than 0.01).
Pimobendan is a long-acting
drug that effectively improves cardiac performance in patients with chronic
congestive heart failure.