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1.1. Adults

The maximum adult H2RA daily doses when prescribed for acute and maintenance FDA-approved conditions are summarized in Table 1 and Table 2. Dosage regimens exceeding these maximum recommended values will be reviewed.

Table 1. Adult Maximum Daily Acute Doses for Histamine H2-Receptor Antagonists: Monotherapy1-10
Drug Name Dosage Form/Strength Treatment Indication Maximum Recommended Dosage 
cimetidine (generics) 200 mg, 300 mg, 400 mg, 800 mg tablets; 300 mg/5 mL oral solution duodenal ulcer 1200 mg/day ^
    gastric ulcer 1200 mg/day
    gastroesophageal reflux disease (GERD) - nonerosive 1600 mg/day
    heartburn 400 mg/day
    hypersecretory conditions 2400 mg/day
famotidine (Pepcid, Zantac 360°, generics) 10 mg, 20 mg, 40 mg tablets; 40 mg/5 mL oral suspension duodenal ulcer 40 mg/day
    erosive esophagitis (EE) 80 mg/day
    gastric ulcer 40 mg/day
    GERD - nonerosive 40 mg/day
    heartburn 40 mg/day
    hypersecretory conditions 640 mg/day
nizatidine (generics) 150 mg, 300 mg capsules; 15 mg/mL oral solution  duodenal ulcer 300 mg/day in single or divided doses
    gastric ulcer 300 mg/day in single or divided doses
    GERD - nonerosive 300 mg/day in single or divided doses

Legend:

  • ^ Patients who are heavy smokers with duodenal ulcers greater than 1 cm may benefit from cimetidine 1600 mg at bedtime.
Table 2. Adult Maximum Daily Maintenance Dose for Histamine H2-Receptor Antagonists: Monotherapy1-10
Drug Name Dosage Form/Strength Treatment Indication Maximum Recommended Dosage 
cimetidine (generics) 200 mg, 300 mg, 400 mg, 800 mg tablets; 300 mg/5 mL oral solution duodenal ulcer 400 mg/day
    hypersecretory conditions 2400 mg/day
famotidine (Pepcid®, generics) 10 mg, 20 mg, 40 mg tablets; 40 mg/5 mL oral suspension duodenal ulcer 20 mg/day
    hypersecretory conditions 640 mg/day
nizatidine (generics) 150 mg, 300 mg capsules; 15 mg/mL oral solution  duodenal ulcer 150 mg/day at bedtime

Current American College of Gastroenterology guidelines recommend the use of a proton pump inhibitor over H2RAs for Helicobacter pylori treatment regimens13.

Currently, famotidine is available as a combination product with ibuprofen, and it is marketed under the trade name Duexis®. Duexis® is FDA approved for the prophylaxis against upper gastrointestinal ulcers in adult patients with osteoarthritis or rheumatoid arthritis.14 Dosing for this agent is provided in Table 3.

Table 3. Adult Maximum Daily Dose for Histamine H2-Receptor Antagonists: Combination Therapy1,2,14
Drug Name Dosage Form/Strength Treatment Indication Maximum Recommended Dosage
famotidine/ ibuprofen (Duexis®, generics) 26.6 mg/ 800 mg oral tablets gastric ulcer prophylaxis in osteoarthritis or rheumatoid arthritis 79.8 mg / 2400 mg/day in three divided doses