What is the recommended duration of amoxicillin (amoxicillin) therapy for gastritis?

From the Guidelines

For gastritis caused by Helicobacter pylori infection, the standard antibiotic duration for amoxicillin is typically 14 days as part of a multi-drug regimen, as recommended by the most recent guidelines 1. The recommended regimen includes amoxicillin 1000 mg twice daily, combined with clarithromycin 500 mg twice daily and a proton pump inhibitor (such as omeprazole 20 mg twice daily) for 14 days, known as triple therapy. Alternatively, quadruple therapy may be used, which includes bismuth subsalicylate, tetracycline, metronidazole, and a proton pump inhibitor for 10-14 days. Some key points to consider when treating H. pylori infection include:

• The importance of adequate acid suppression, which can be achieved with standard doses of proton pump inhibitors (PPIs) such as pantoprazole 40mg, lansoprazole 30mg, omeprazole 20mg, esomeprazole 20mg, dexlansoprazole 30mg, or rabeprazole 20mg, taken 30 minutes prior to eating or drinking on an empty stomach, without concomitant use of other anti-acids 1.
• The potential benefits of higher doses of metronidazole (at least 1.5-2 g/day) in improving eradication rates, although these higher doses may be poorly tolerated due to gastrointestinal and other side effects 1.
• The value of dividing amoxicillin into at least three doses daily to avoid low trough levels and improve the efficacy of eradication therapy 1. It's essential to complete the full course of antibiotics even if symptoms improve before completion to ensure eradication of H. pylori and prevent antibiotic resistance. Treatment success should be confirmed with a urea breath test, stool antigen test, or endoscopy with biopsy at least 4 weeks after completing therapy and after being off proton pump inhibitors for at least 2 weeks. The 14-day duration is preferred over shorter courses because it has been shown to increase eradication rates of H. pylori, which is crucial for preventing recurrence of gastritis and reducing the risk of complications like peptic ulcers and gastric cancer 1.

From the FDA Drug Label

1. 4 Dosage for H. pyloriInfection in Adults Triple therapy:The recommended adult oral dose is 1 gram amoxicillin, 500 mg clarithromycin, and 30 mg lansoprazole, all given twice daily (every 12 hours) for 14 days. Dual therapy:The recommended adult oral dose is 1 gram amoxicillin and 30 mg lansoprazole, each given three times daily (every 8 hours) for 14 days.

The recommended antibiotic duration for gastritis caused by H. pylori using amoxicillin is 14 days 2.

• The dosage is either 1 gram amoxicillin twice daily in combination with clarithromycin and lansoprazole, or 1 gram amoxicillin three times daily in combination with lansoprazole.
• This treatment is intended to eradicate H. pylori and reduce the risk of duodenal ulcer recurrence.

From the Research

Antibiotic Duration for Gastritis with Amoxicillin

• The duration of antibiotic treatment for gastritis with amoxicillin can vary depending on the specific regimen and the patient's condition 3, 4, 5, 6, 7.
• A 7-day triple regimen composed of a proton pump inhibitor, clarithromycin, and amoxicillin has been shown to be effective in eradicating H. pylori infection 3, 6, 7.
• A 5-day quadruple regimen adding amoxicillin to a triple regimen of metronidazole, omeprazole, and clarithromycin has also been found to be effective 4.
• The importance of clarithromycin dose in the management of H. pylori infection has been highlighted, with a dose of 500 mg b.d. being more effective than 250 mg b.d. in proton pump inhibitor-based triple therapies 7.
• The eradication rates of H. pylori infection with different regimens and durations of treatment have been reported to be:
  • 74.5% and 80.4% for a 7-day triple regimen of lansoprazole, clarithromycin, and amoxicillin 3
  • 96.4% and 100% for a 7-day triple regimen of omeprazole, metronidazole, and amoxicillin 3
  • 96% and 92% for a 5-day quadruple regimen of omeprazole, metronidazole, clarithromycin, and amoxicillin 4
  • 90.4% and 87.9% for a 1-week course of famotidine, amoxicillin, and clarithromycin 5
  • 89.6%, 95.7%, and 71.7% for a 1-week or 2-week course of omeprazole, clarithromycin, and amoxicillin, or colloidal bismuth subcitrate, amoxicillin, and metronidazole 6