What is this medicine for Famotidine?
Famotidine belongs to the group of active substances called H2-receptor antagonists and inhibits acid secretion in the stomach. The medicine is used to treat stomach and intestinal ulcers and Zollinger-Ellison syndrome.
The active ingredient famotidine is used to treat the following diseases in which a decrease in gastric acid secretion is indicated:
- Duodenal ulcer (ulcera duodeni)
- benign stomach ulcers (gastric ulcers)
- Zollinger-Ellison Syndrome
Type of application
Famotidine is approved for oral use in the form of film-coated tablets.
Mechanism of action
Famotidine is a competitive antagonist of the histamine H2 receptor in the parietal cells of the gastric mucosa. The inhibition leads to a reduction in gastric acid secretion and the release of pespsin.
Famotidine is subject to linear kinetics. The bioavailability is approximately 40%. Peak plasma concentrations are dose-dependent and are reached approx. 1 to 3.5 hours after ingestion. Repeated doses do not lead to an accumulation of active substances and simultaneous food intake does not affect famotidine absorption.
Famotidine is only bound to plasma proteins to a small extent (15 to 22%).
Famotidine is eliminated in breast milk. The milk / plasma concentration ratio is 1.73 6 hours after oral administration.
30 to 35% of the active substance is metabolized in the liver and a sulfoxide metabolite is formed.
After oral administration, 25 to 30% of the dose and after intravenous administration 65 to 70% of the dose are eliminated unchanged renally within 24 hours. Renal clearance is 250-450 ml / min, suggesting tubular excretion. The plasma elimination half-life is 2.6 to 4 hours.
Duodenal ulcers and benign gastric ulcers
The recommended dose is 40 mg famotidine once in the evening before going to bed.
Unless pretreatment with anti-secretory drugs has been performed, the recommended dose is 20 mg famotidine every 6 hours. The dose depends on the severity of the clinical picture and on the dosage of the drug previously used.
Impaired kidney function
Famotidine is mainly eliminated via the kidneys. In patients with impaired renal function or on dialysis patients, a reduction of the daily dose to 50% is recommended.
Common side effects (≥ 1/100 to <1/10) with the use of famotidine include:
- Headache, dizziness
- Diarrhea, constipation
The following interactions must be observed when using famotidine:
- By changing the gastric pH value, the bioavailability of certain drugs can be influenced, such as atazanavir , ketoconazole , itraconazole . Ketoconazole should therefore be administered 2 hours before the administration of famotidine.
- If calcium carbonate is used as a phosphate binder at the same time as famotidine in hemodialysis patients, there is a risk of a loss of effectiveness of calcium carbonate.
- Antacids can decrease the absorption of famotidine and lead to lower famotidine plasma concentrations. Famotidine should therefore be taken 1 to 2 hours before the administration of an antacid.
- Sucralfate decreases the absorption of famotidine. Therefore, sucralfate should be taken 2 hours apart from the administration of famotidine.
- Probenecid may delay the excretion of famotidine. Simultaneous use of famotidine and probenecid should be avoided.
Famotidine must not be used in:
- Hypersensitivity to the active substance or any of the other ingredients of the drug in question
- Hypersensitivity to other H2-receptor antagonists
Pregnancy / lactation
Famotidine may only be used during pregnancy after carefully weighing the expected benefits against possible risks.
Famotidine is excreted in breast milk. Since a disruption of gastric acid secretion in the infant due to ingested famotidine cannot be ruled out, breastfeeding should be avoided during treatment.
Ability to drive
Some patients responded to taking famotidine with side effects such as dizziness and headache. Patients should be informed to avoid driving, using machines, or doing activities that require full attention if these symptoms occur.