Ranitidine kinetics and dynamics. II. Intravenous dose studies and comparison with cimetidine.
Intravenous ranitidine has been shown to reduce pentagastrin-stimulated gastric secretion. Eight normal men received, in randomized order, 60 mg ranitidine or 300 mg cimetidine intravenously over 2 min. Both ranitidine and cimetidine induced decreases in volume hydrogen ion content and pepsin activity of stimulated gastric juice. Ranitidine half-life (t1/2) was 2.1 +/- 0.1 hr and cimetidine (t1/2) was 1.5 +/- 0.1 hr. Ranitidine volume of distribution was 1.6 +/- 0.1 l/kg and that of cimetidine was 1.12 +/- 0.12 l/kg. The clearance of ranitidine was 0.54 +/- 0.04 l/kg hr-1 and that of cimetidine was 0.5 +/- 0.05 l/kg hr-1. It is suggested that the intravenous loading dose of ranitidine necessary to attain a serum concentration of 200 micrograms/l (which would achieve a 50% inhibition of gastric acid) is 0.3 mg/kg, followed by an infusion rate of 0.11 mg/kg hr-1.
D000328:Adult; D002927:Cimetidine / Q000008:administration & dosage / Q000097:blood*; D005663:Furans / Q000008:administration & dosage / Q000097:blood*; D005753:Gastric Mucosa / Q000187:drug effects / Q000378:metabolism; D006146:Guanidines / Q000097:blood*; D006801:Humans; D007275:Injections, Intravenous; D007700:Kinetics; D008297:Male; D011899:Ranitidine
D005663:Furans; D006146:Guanidines; D002927:Cimetidine; D011899:Ranitidine