antagonists-cimetidine and ranitidine
نویسندگان
چکیده
Few drugs have so rapidly gained an established place in modern medicine as the histamine H, receptor antagonists. As a result of the inventiveness of James Black and his colleagues, the theoretical concept of a second class of histamine receptors became a therapeutic reality. The failure of classic antihistamine drugs (more appropriately H1 receptor antagonists) to block the actions of histamine, particularly on gastric acid secretion but also on isolated heart and uterine muscle, may now be explained by the existence of both H1 and H2 receptors which can be blocked by their respective specific H1 or H2 antagonists (table).
منابع مشابه
Effects of H2-receptor antagonists on 3H-cimetidine binding and histamine-stimulation of cellular cAMP in isolated guinea pig gastric glands.
3H-Cimetidine binding to plasma membranes of isolated guinea pig gastric glands was investigated, and the effects of five H2-receptor antagonists on 3H-cimetidine binding and histamine stimulation of cellular cAMP were compared. Of the five cations tested, Cu++ markedly increased specific 3H-cimetidine binding. 3H-Cimetidine had high affinity (Kd = 0.41 x 10(-6) M) and low affinity (Kd = 12.8 x...
متن کاملPotent radioprotective effect of therapeutic doses of ranitidine and famotidine against gamma-rays induced micronuclei in vivo
Background: Previous investigations have revealed, cimetidine, a histamine H2-receptor antagonist, show radioprotective effects against gamma- and neutron-induced micronuclei in bone marrow erythrocytes. In this study, the anticlastogenic effects of famotidine and ranitidine, which act similar to cimetidine as histamine H2-receptor antagonists, was investigated. Materials and Methods : Balb/c m...
متن کاملSingle nocturnal dose of an H2 receptor antagonist for the treatment of duodenal ulcer.
Twenty four hour intragastric acidity and nocturnal acid output have been measured over five separate 24 hour periods in each of 12 patients with duodenal ulcer receiving either placebo, cimetidine 400 mg bd, cimetidine 300 mg nocte, ranitidine 150 mg bd, or ranitidine 300 mg nocte. In these doses ranitidine was significantly more effective at decreasing intragastric acidity and nocturnal acid ...
متن کاملInhibition of gastric acid secretion in the dog by the H2-receptor antagonists, ranitidine, cimetidine, and metiamide.
The new H2-receptor antagonist, ranitidine, has been compared with cimetidine and metiamide as an inhibitor of gastric acid secretion in the dog. All three compounds were effective both intravenously or by mouth in inhibiting secretion induced by histamine, pentagastrin, or bethanechol. This inhibition was mainly attributable to a reduction in the volume of secretion, although there was also a ...
متن کاملA species difference in the transport activities of H2 receptor antagonists by rat and human renal organic anion and cation transporters.
A clinical drug-drug interaction between famotidine (a H2 receptor antagonist) and probenecid has not been reproduced in rats. The present study hypothesized that the species-dependent probenecid sensitivity is due to a species difference in the contribution of renal organic anion and cation transporters. The transport activities of the H2 receptor antagonists (cimetidine, famotidine, and ranit...
متن کاملSingle-dose intravenous H2 blocker prophylaxis against aspiration pneumonitis: assessment of drug concentration in gastric aspirate.
This placebo-controlled trial compared the effects of preoperative, intravenous cimetidine (300 mg) or ranitidine (50 mg) on gastric pH and gastric volume in 31 adult patients requiring general anesthesia. The elapsed time from drug administration to initial gastric sampling did not differ significantly between ranitidine (45 minutes), cimetidine (48 minutes), or placebo (52 minutes) treated pa...
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