Tiotidine, a new long-acting histamine H2-receptor antagonist: comparison with cimetidine.
The effects of tiotidine, a new histamine H2-receptor antagonist, and cimetidine on food-stimulated gastric acid secretion were evaluated in duodenal ulcer patients. Homogenized steak meals were infused immediately after, 1 h after, 5 h after, and 10 h after an oral dose of medication, and food-stimulated acid secretion was measured by in vivo intragastric titration. Tiotidine and cimetidine had a similar onset of action; however, tiotidine was more potent and had a longer duration of effect. Increased potency was demonstrated by the fact that from 1 to 2 h after medication 150 mg tiotidine inhibited acid secretion to approximately the same extent as did 300 mg cimetidine, and by the fact that for a given percent inhibition of acid secretion, plasma tiotidine concentration was eight to nine times lower than plasma cimetidine concentration. Longer duration of effect was demonstrated by the fact that from 5 to 7 h after medication, acid secretion was inhibited by 80% and 97% with 150 and 300 mg tiotidine, respectively, whereas 300 mg cimetidine inhibited acid secretion by only 22%. Also, 10-12 h after medication, 150 and 300 mg tiotidine inhibited acid secretion by 22% and 53%, respectively, while 300 mg cimetidine had no inhibitory effect. The long duration of effect was due in part to increased potency and in part to a plateau in plasma concentration of tiotidine, which was maintained from 2 to 6 h after medication. Neither tiotidine nor cimetidine had a significant effect on food-stimulated gastrin release or gastric emptying of a nonabsorbable marker.
D000328:Adult; D002927:Cimetidine / Q000097:blood / Q000494:pharmacology* / Q000031:analogs & derivatives; D004381:Duodenal Ulcer / Q000188:drug therapy / Q000503:physiopathology; D005744:Gastric Acid / Q000378:metabolism; D005746:Gastric Emptying / Q000187:drug effects; D005755:Gastrins / Q000097:blood; D006146:Guanidines / Q000097:blood / Q000494:pharmacology*; D006635:Histamine H2 Antagonists / Q000097:blood / Q000494:pharmacology*; D006801:Humans; D008875:Middle Aged; D011092:Polyethylene Glycols / Q000378:metabolism; D013844:Thiazoles / Q000097:blood / Q000494:pharmacology*
D005755:Gastrins; D006146:Guanidines; D006635:Histamine H2 Antagonists; D013844:Thiazoles; D011092:Polyethylene Glycols; D002927:Cimetidine; C023990:tiotidine