Kinetics of medroxalol, a β‐ and α‐adrenoceptor antagonist

Eight healthy men received single oral doses of 400, 800, and 1200 mg medroxalol and a single intravenous dose of 1 mg per kg body weight on four occasions separated by at least 2 wk. Plasma medroxalol concentrations were assayed up to 24 hr after each dose by a specific high‐pressure liquid Chromatographic assay. Urinary excretion of parent compound was determined as well. Following oral doses medroxalol reached peak plasma concentrations within 2.5 to 3 hr. The t½ of the terminal decay phase was 11.1 hr. Mean apparent volume of distribution (aVD) was between 11.2 and 16.4 l/kg, and mean total body clearance (Cl T ) was between 0.73 and 0.99 l hr −1 kg −1 . Mean urinary recovery of parent drug within 48 hr was 2.3%, 3.9%, and 3.6% after the oral doses compared to 8.2% after the intravenous dose. Bioavailability estimated from AUC was 27.2% after 400 mg, 31.3% after 800 mg, and 37.4% after 1200 mg by mouth. Since aVD, t½, Cl T , and urinary excretion did not differ significantly after the three oral doses, medroxalol kinetics appear to follow a dose‐linear model. Clinical Pharmacology and Therapeutics (1983) 34 , 785–791; doi: 10.1038/clpt.1983.250