From the Guidelines
Famotidine is effective in preventing gastrointestinal (GI) upset associated with antibiotic use, as evidenced by its ability to reduce the incidence of peptic ulcers and erosive esophagitis in patients taking low-dose aspirin. The FAMOUS trial, a phase II, double-blind, randomized, placebo-controlled trial, found that among patients with a history of coronary heart disease, diabetes mellitus, or cerebrovascular disease who were taking low-dose ASA, 12 weeks of famotidine 20 mg twice daily was beneficial in reducing the incidence of peptic ulcer or hematomas of 5 cm, intracranial hemorrhage, and bleeding that required surgery 1.
Key Findings
- The rate of occurrence of a gastric ulcer at endoscopy at 12 weeks was 3.4% in the famotidine group versus 15% in the placebo group (P0.0002) 1.
- Duodenal ulcer occurred in 0.5% versus 8.5% (P0.0045) 1.
- Erosive esophagitis was seen in 4.4% versus 19% (P0.0001) 1.
- Famotidine can be used to prevent GI upset associated with antibiotic use, though it's not routinely recommended for all patients taking antibiotics.
Recommendations
- For those experiencing or at high risk of GI symptoms, famotidine 20mg taken once or twice daily before antibiotic doses may help reduce stomach discomfort, nausea, and heartburn.
- Simple measures like taking antibiotics with food (unless contraindicated) and maintaining adequate hydration should be tried first, as not all antibiotic-related GI symptoms require medication intervention.
- For severe symptoms or those with a history of ulcers, consultation with a healthcare provider is recommended before starting famotidine.
From the FDA Drug Label
12.1 Mechanism of Action Famotidine is a competitive inhibitor of histamine-2 (H2) receptors. The primary clinically important pharmacologic activity of famotidine is inhibition of gastric secretion. 12.2 Pharmacodynamics Adults Famotidine inhibited both basal and nocturnal gastric secretion, as well as secretion stimulated by food and pentagastrin.
The FDA drug label does not answer the question.
From the Research
Effectiveness of Famotidine in Preventing GI Upset
- Famotidine is a highly selective histamine H2-receptor antagonist that is effective in healing both duodenal and gastric ulcers 2.
- It has been shown to be approximately 20 to 50 times more potent at inhibiting gastric acid secretion than cimetidine and 8 times more potent than ranitidine on a weight basis 2.
- Famotidine is also effective in preventing recurrence of duodenal ulcer and as initial or maintenance treatment of gastric hypersecretory disorders, but further clinical experience is needed to define its relative efficacy and tolerability in these indications 2.
Use of Famotidine in Gastroesophageal Reflux Disease (GERD)
- Famotidine has been evaluated in patients with GERD and has been shown to be effective in achieving adequate results with b.i.d. dosing 3.
- It has been compared to cimetidine and ranitidine in large double-blind trials and has been found to be effective in ranitidine-resistant patients with severe GERD 3.
- Long-term treatment with famotidine has also been shown to be effective in preventing recurrence in most patients with healed reflux esophagitis 3.
Comparison with Other H2-Receptor Antagonists
- Famotidine has been compared to other H2-receptor antagonists such as cimetidine and ranitidine in several studies and has been found to be approximately equivalent to cimetidine and ranitidine in the treatment of acute duodenal ulcer 4.
- It has also been found to be superior to gefarnate in the treatment of acute duodenal ulcer and acute gastric ulcer 4.
Safety and Tolerability
- Famotidine has been shown to be very well tolerated and is free of the antiandrogenic effects infrequently reported with cimetidine 2.
- It is not associated with altered hepatic metabolism of drugs and has a favorable side effect profile with adverse reactions being rare and never positively associated with the drug 2, 4.