Dobutamine pharmacokinetics in severe heart failure.

Dobutamine pharmacokinetics was investigated in 7 patients with severe cardiac failure. Dobutamine was administered by a constant intravenous infusion at rates of 2.5, 5.0, 7.5, and 10.0 microgram/kg/min. Steady-state plasma levels increased in proportion to the infusion rate, indicating that there was no saturation of the disposition processes. The average total body clearance was found to be 2.35 +/- 1.01 L/min/m2. After termination of the final infusion, plasma levels of dobutamine were monitored to determine the elimination half-life. The disappearance half-life of dobutamine was calculated to be 2.37 +/- 0.7 min and the distribution volume was 0.202 +/- 0.084 L/kg. The limited data suggest that the volume of distribution of dobutamine was related to the extent of edema.