Prescribing-label excerpts
Cimetidine
Reference for: Cimetidine. Source presentation: tablet, film coated. Source route: oral.
The source label presents its clinical-pharmacology findings together. These selected passages retain the source’s study context; the full label provides the complete discussion.
Clinical pharmacology
Cimetidine tablets competitively inhibits the action of histamine at the histamine H2 receptors of the parietal cells and thus is a histamine H2-receptor antagonist.
Cimetidine is not an anticholinergic agent. Studies have shown that cimetidine tablets inhibit both daytime and nocturnal basal gastric acid secretion. Cimetidine tablets also inhibit gastric acid secretion stimulated by food, histamine, pentagastrin, caffeine and insulin.
Cimetidine tablets are rapidly absorbed after oral administration and peak levels occur in 45 to 90 minutes. The half-life of cimetidine tablets is approximately 2 hours. Blood concentrations remain above that required to provide 80% inhibition of basal gastric acid secretion for 4 to 5 hours following a dose of 300 mg.
Following parenteral administration, most of the drug is excreted as the parent compound in the urine, the principle route of excretion of cimetidine tablets. After oral administration, the drug is extensively metabolized in which the sulfoxide is the major metabolite. Following a single oral dose, 48% of the drug is recovered from the urine after 24 hours as the parent compound.
Selected passages from the cited U.S. prescribing label. The studies concern the source product and populations named in each passage; they do not establish Walter-product bioequivalence, an approved indication, or the kinetics of another fixed combination. Tables and the full prescribing information remain available in the source.
Source: DailyMed: Cimetidine — tablet, film coated
Reference accessed . Label revision: 2026-07-15.
