The pharmacokinetics of indoramin (Baratol) have been studied in five male and five female healthy, middle-aged volunteers after intravenous administration (0.14 mg/kg). Elimination occurred in an apparently biexponential fashion with a mean elimination half-life of 4.0 h (+/- 0.25 SEM). The mean plasma clearance was 19.9 ml/min/kg (+/- 1.32 SEM) and the mean volume of distribution 7.4 l/kg (+/- 0.81 SEM). There were no significant differences in these parameters between male and female volunteers. Protein binding of indoramin ranged from 85.6% at 81 ng/ml to 72.2% at 129 micrograms/ml. Two classes of binding site were evident, with affinity constants of 6.85 X 10(4)M -1 and 4.30 X 10(3)M -1.