Famotidine (Pepsid) Dosing for Duodenal Ulcers and GERD
For active duodenal ulcers, use famotidine 40 mg once daily at bedtime or 20 mg twice daily for up to 8 weeks; for GERD, use 20 mg twice daily for up to 6 weeks for symptomatic non-erosive disease or up to 12 weeks for erosive esophagitis. 1
Standard Dosing by Indication
Active Duodenal Ulcer
- 40 mg once daily at bedtime OR 20 mg twice daily for up to 8 weeks 1
- Most patients heal within 4 weeks; if unhealed, consider an additional 2-4 weeks of treatment 1
- Both dosing regimens demonstrated equivalent effectiveness in clinical trials 1, 2
Active Gastric Ulcer
- 40 mg once daily for up to 8 weeks 1
- Healing rates of 80% at 4 weeks and 94.3% at 8 weeks have been documented 3
Gastroesophageal Reflux Disease (GERD)
- Symptomatic non-erosive GERD: 20 mg twice daily for up to 6 weeks 1
- Erosive esophagitis (endoscopically confirmed): 20 mg twice daily OR 40 mg twice daily for up to 12 weeks 1
Maintenance Therapy for Duodenal Ulcer Recurrence Prevention
- 20 mg once daily at bedtime for up to 1 year 1
- This reduces cumulative relapse rates to 23.3% at 12 months compared to 56.8% with placebo 4
Administration Guidelines
Timing and Food Interactions
- Take once-daily doses at bedtime; take twice-daily doses in the morning and before bedtime 1
- Famotidine may be taken with or without food, as absorption is not significantly affected by food intake 5, 1
- Can be administered with antacids if needed for breakthrough symptom relief 5, 1
Dosing Adjustments for Renal Impairment
Moderate Renal Impairment (CrCl 30-60 mL/min)
- Active duodenal ulcer: 20 mg once daily OR 40 mg every other day 1
- GERD (non-erosive): 20 mg once daily 1
- Erosive esophagitis: 20 mg once daily OR 40 mg every other day 1
Severe Renal Impairment (CrCl <30 mL/min)
- All indications: 20 mg every other day (or 10 mg once daily using alternate formulation) 1
Important Clinical Considerations
Comparative Efficacy Context
- PPIs are more effective than H2-receptor antagonists (including famotidine) for esophageal GERD syndromes 5
- However, famotidine is 20-50 times more potent than cimetidine and 8 times more potent than ranitidine on a weight basis 2, 6
- Famotidine achieves healing rates similar or superior to cimetidine 800 mg daily or ranitidine 300 mg daily 2
Tachyphylaxis Warning
- Decreased response (tachyphylaxis) can develop within 6 weeks of initiating H2-receptor antagonist therapy, which may limit long-term effectiveness 5
- This is a critical consideration when planning extended therapy
Special Population: Dual Antiplatelet Therapy
- In patients taking clopidogrel with aspirin, famotidine may be preferred over PPIs due to potential drug interactions between PPIs and clopidogrel 7, 5
- The FDA notes that H2 blockers do not interfere with the antiplatelet activity of clopidogrel 7
- Famotidine 20 mg twice daily reduced gastric ulcer incidence from 15% to 3.4% and duodenal ulcer from 8.5% to 0.5% in patients on low-dose aspirin 7
Safety Profile
- Unlike cimetidine, famotidine is not associated with antiandrogenic effects, gynecomastia, or altered hepatic drug metabolism 5, 2, 6
- Very well tolerated with minimal adverse effects in clinical trials 2, 3
Duration of Action
- Acid-inhibiting effects last approximately 6 hours, necessitating multiple daily doses for continuous coverage 5