title: Comparison of the clinical pharmacokinetics and concentration-effect relationships for medroxalol and labetalol.
abstract: The pharmacokinetics of medroxalol are described in normal subjects and compared with those of labetalol. Both drugs were administered in doses of 400 mg orally and 1 mg/kg intravenously. The data for both drugs was most appropriately described by a two compartment model. For oral medroxalol the clinical pharmacokinetic parameters were a terminal elimination half-life (t 1/2,Z) of 15.6 h, a peak level of 450 ng/ml and a time to peak of 2-3 h. Following intravenous medroxalol the bioavailability was calculated as 64%, the plasma clearance was 948 ml/min and the t 1/2,Z was 7.3 h. The t 1/2,Z following intravenous administration was significantly shorter than that following oral administration. The significant differences between medroxalol and labetalol were in time to peak, respectively 2.3 and 1.1 h; oral t 1/2,Z, 15.6 and 5.5 h; clearance 948 and 1560 ml/min; and bioavailability, 64 and 20%. Despite the pharmacokinetic differences a similar plasma concentration-hypotensive effect relationship was described for each drug.
mesh_terms: D000317:Adrenergic alpha-Antagonists / Q000378:metabolism* / Q000494:pharmacology; D000319:Adrenergic beta-Antagonists / Q000378:metabolism* / Q000494:pharmacology; D000328:Adult; D001682:Biological Availability; D001794:Blood Pressure / Q000187:drug effects*; D004311:Double-Blind Method; D004341:Drug Evaluation; D004983:Ethanolamines / Q000378:metabolism* / Q000494:pharmacology; D006207:Half-Life; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007700:Kinetics; D007741:Labetalol / Q000378:metabolism* / Q000494:pharmacology; D008297:Male; D011187:Posture; D013997:Time Factors
chemical_list: D000317:Adrenergic alpha-Antagonists; D000319:Adrenergic beta-Antagonists; D004983:Ethanolamines; C024892:medroxalol; D007741:Labetalol