Ranitidine bioavailability and kinetics in normal male subjects.
Ranitidine is a potent histamine H2-receptor blocker that inhibits histamine- and pentagastrin-induced gastric acid secretion. After doses of 100 mg both intravenously and orally ranitidine kinetics and bioavailability were investigated in a single dose two-way crossover study in 12 normal men. Serum concentrations of ranitidine were determined by radioimmunoassay and urine concentrations by an ion-pair HPLC method. Intravenous data were fitted to exponential equations with the computer program NONLIN; model-independent kinetic parameters were calculated. Elimination t 1/2, plasma clearance, renal clearance, hepatic clearance, and volume of distribution for ranitidine after intravenous injection were 2 hr, 10.4 ml/(min X kg), 7.2 ml/(min X kg), 3.1 ml/(min X kg), and 1.82 l/kg, respectively; after oral doses mean t 1/2 was 2.7 hr and mean bioavailability was 52%. The average cumulative urinary excretion of ranitidine as percent of dose was 69.4 +/- 6.1% and 26.7 +/- 7.2% after intravenous and oral doses.
D000284:Administration, Oral; D000328:Adult; D001682:Biological Availability; D001794:Blood Pressure / Q000187:drug effects; D005663:Furans / Q000008:administration & dosage / Q000378:metabolism* / Q000652:urine; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007275:Injections, Intravenous; D007700:Kinetics; D008297:Male; D011863:Radioimmunoassay; D011899:Ranitidine
D005663:Furans; D011899:Ranitidine