Pharmacotherapeutic group: histamine H
2
-receptor antagonist, guanylthiazole derivative, ATC code: A02BA03
Mechanism of action
Famotidine is a competitive histamine H
2
-receptor antagonist which leads to an inhibition of acid secretion mediated by H
2
-receptors. Beside the acidity the pepsin content and the volume of basal gastric juice as well as that formed after stimulation is reduced. A pharmacological effect on the CNS, immunological, cardiovascular or respiratory parameters could not be observed.
Pharmacodynamic effects, clinical efficacy and safety
After oral administration the effect begins within one hour and reaches its maximum after 1-3 hours.
Single oral doses of 20 and 40 mg reliably inhibited basal nocturnal acid secretion. Mean gastric acid secretion was inhibited over at least 10 hours by 86 to 94%. The same doses administered in the morning suppressed the acid secretion stimulated by food 3-5 hours after administration by, on average, 76 to 84% and 8-10 hours after ingestion by 25 to 30%. However, the duration of action of the 20 mg dose in some subjects lasted 6-8 hours. Repeated doses did not lead to an accumulation of active constituent.
The nocturnal basal intragastric pH value was elevated by evening administration of 20 and 40 mg famotidine to an average of 5 and 6.4 respectively. If famotidine was taken after breakfast the pH value after 3 and after 8 hours was increased on the 20 mg as well as the 40 mg dose of famotidine to about 5.
Fasting and postprandial serum gastrin concentrations were not influenced by famotidine or only very slightly. Emptying of the stomach and exocrine pancreatic function were not affected by famotidine. The same applies to hepatic and portal blood flow. Famotidine had no effect on endocrinological functions either. Hormone concentrations of prolactin, cortisone, thyroxine (T4) and testosterone remained unchanged on treatment with famotidine.
⚠️ Warnings
Any unused product or waste material should be disposed of in accordance with local requirements.