What are the guidelines for Famotidine (Pepcid) usage?

From the Guidelines

Famotidine is a suitable alternative to proton pump inhibitors (PPIs) for patients on dual-antiplatelet therapy, as it does not interfere with the metabolism of clopidogrel, according to the 2009 ACC/AHA guidelines 1. When considering the use of famotidine in patients with acute coronary syndrome (ACS), it is essential to weigh the benefits of reducing gastrointestinal complications against the potential risks of interacting with antiplatelet therapy.

• The 2009 ACC/AHA guidelines suggest that PPIs, such as omeprazole, lansoprazole, and rabeprazole, may interfere with the metabolism of clopidogrel, potentially leading to adverse cardiovascular outcomes 1.
• In contrast, famotidine, an H2 blocker, has been shown to be beneficial in reducing the incidence of peptic ulcer or esophagitis in patients taking low-dose aspirin, without interfering with clopidogrel metabolism, as demonstrated in the FAMOUS trial 1.
• The standard dosage of famotidine for reducing stomach acid production is 20mg twice daily or 40mg once daily, and it is generally preferred over older H2 blockers due to fewer drug interactions and side effects.
• Patients with kidney disease may require dose adjustments, and famotidine should be taken 1-2 hours before meals for optimal effect.
• While generally well-tolerated, potential side effects of famotidine include headache, dizziness, and constipation.
• The FDA notes that there is no evidence that H2 blockers, such as famotidine, interfere with the antiplatelet activity of clopidogrel, making it a suitable alternative to PPIs in patients on dual-antiplatelet therapy 1.

From the FDA Drug Label

1. 1 Recommended Dosage Table 1 shows the recommended dosage of Famotidine 20 mg and 40 mg tablets in adults and pediatric patients weighing 40 kg or greater with normal renal function.

Indication Recommended Dosage Recommended Duration Active duodenal ulcer (DU) 40mg once daily; or 20mg twice daily a Up to 8 weeks b,c Active gastric ulcer 40mg once daily Up to 8 weeks Symptomatic non-erosive GERD 20mg twice daily Up to 6 weeks c Erosive esophagitis diagnosed by endoscopy 20mg twice daily; or 40mg twice daily a Up to 12 weeks Pathological hypersecretory conditions d Starting dosage: 20mg every 6 hours; adjust dosage to individual patient needs Maximum dosage 160mg every 6 hours As clinically indicated Reduction of the risk of DU recurrence d 20mg once daily 1 year c or as clinically indicated

The guidelines for Famotidine usage are as follows:

• Active duodenal ulcer (DU): 40mg once daily or 20mg twice daily for up to 8 weeks
• Active gastric ulcer: 40mg once daily for up to 8 weeks
• Symptomatic non-erosive GERD: 20mg twice daily for up to 6 weeks
• Erosive esophagitis diagnosed by endoscopy: 20mg twice daily or 40mg twice daily for up to 12 weeks
• Pathological hypersecretory conditions: starting dosage of 20mg every 6 hours, with a maximum dosage of 160mg every 6 hours, as clinically indicated
• Reduction of the risk of DU recurrence: 20mg once daily for 1 year or as clinically indicated 2

From the Research

Famotidine Guidelines

• Famotidine is a highly selective histamine H2-receptor antagonist, 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 3.
• Famotidine is effective in healing both duodenal and gastric ulcers, with healing rates and symptom relief similar or superior to those achieved by cimetidine or ranitidine in patients with peptic ulcer disease 3.
• Famotidine may be effective in the treatment of gastritis and reflux gastro-oesophagitis, with suggested dosages of 10 to 20mg twice daily 3.
• In patients with Zollinger-Ellison syndrome, famotidine may confer an advantage over other H2-receptor antagonists due to its potency and long duration of action 3.
• Famotidine is also effective in the treatment of gastroesophageal reflux disease (GERD), with b.i.d. dosing necessary for achieving adequate results 4.
• Comparative trials have shown that famotidine is similar in efficacy to cimetidine in the treatment of upper gastrointestinal bleeding and to ranitidine in the prevention of pulmonary aspiration of acid 3.
• Long-term treatment with famotidine seems to be effective in preventing recurrence in most patients with healed reflux esophagitis 4.
• However, omeprazole has been shown to be superior to famotidine in the treatment of upper abdominal symptoms in patients with reflux esophagitis 5.
• A prospective randomized multicentre trial found that omeprazole is more effective than famotidine for the control of gastro-oesophageal reflux disease symptoms in H. pylori-negative patients, while similar efficacy is observed in H. pylori-positive patients with non-erosive gastro-oesophageal reflux disease 6.

Dosage and Administration

• Famotidine 20mg twice daily or 40mg at bedtime is effective in healing duodenal and gastric ulcers 3.
• Famotidine 10 to 20mg twice daily may be effective in the treatment of gastritis and reflux gastro-oesophagitis 3.
• B.i.d. dosing of famotidine is necessary for achieving adequate results in the treatment of GERD 4.

Comparison with Other Treatments

• Famotidine is 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 3.
• Omeprazole has been shown to be superior to famotidine in the treatment of upper abdominal symptoms in patients with reflux esophagitis 5.
• A combination of proton-pump inhibitors (PPIs) and histamine(2) receptor antagonists may not provide any further benefit above that derived from PPIs alone in the treatment of GERD 7.