What is the recommended treatment for a patient with gastritis, possibly caused by H. pylori infection, and what are the initial medication options, such as proton pump inhibitors (PPIs) like omeprazole (Prilosec) or lansoprazole (Prevacid), and antibiotics like amoxicillin and clarithromycin?

Treatment of Gastritis

First-Line Treatment for H. pylori-Positive Gastritis

Bismuth quadruple therapy for 14 days is the recommended first-line treatment for H. pylori-associated gastritis, consisting of a high-dose PPI twice daily, bismuth subsalicylate, metronidazole, and tetracycline, achieving 80-90% eradication rates even in areas with high antibiotic resistance. 1

Specific Bismuth Quadruple Therapy Regimen

• Esomeprazole or rabeprazole 40 mg twice daily (preferred over other PPIs as they increase cure rates by 8-12%) 1, 2
• Bismuth subsalicylate 262 mg (2 tablets) four times daily, taken 30 minutes before meals 1
• Metronidazole 500 mg three to four times daily (total 1.5-2 g daily) 1, 2
• Tetracycline 500 mg four times daily 1, 2
• Duration: 14 days mandatory (improves eradication by approximately 5% compared to shorter regimens) 1, 2

Critical Optimization Factors

• Take PPI 30 minutes before meals on an empty stomach, without concomitant use of other antacids 1, 3
• Bismuth quadruple therapy is not affected by clarithromycin resistance and metronidazole resistance in vitro does not significantly affect outcomes because bismuth's synergistic effect overcomes this resistance 1
• No bacterial resistance to bismuth has been described, and tetracycline resistance remains rare 1

Alternative First-Line Option (Only in Specific Circumstances)

Concomitant non-bismuth quadruple therapy may be considered when bismuth is unavailable, consisting of PPI twice daily, amoxicillin 1000 mg twice daily, clarithromycin 500 mg twice daily, and metronidazole 500 mg twice daily for 14 days. 1, 2

When Triple Therapy May Be Considered

• Triple therapy with PPI, clarithromycin, and amoxicillin should only be used in areas with documented clarithromycin resistance below 15%, and even then, bismuth quadruple therapy is superior 1, 2
• Standard triple therapy regimen: Esomeprazole or rabeprazole 40 mg twice daily, clarithromycin 500 mg twice daily, amoxicillin 1000 mg twice daily for 14 days 1, 4, 5
• Clarithromycin resistance now exceeds 15-20% in most of North America and Central, Western, and Southern Europe, making traditional triple therapy achieve only 70% eradication rates 1

Treatment for Non-H. pylori Gastritis (NSAID-Associated or Erosive)

For NSAID-associated gastritis or erosive gastritis without H. pylori, PPIs are the treatment of choice, as they are superior to H2-receptor antagonists and misoprostol in healing gastroduodenal lesions and controlling symptoms. 2

PPI Therapy for Non-H. pylori Gastritis

• Standard dose PPI once daily (omeprazole 20 mg, lansoprazole 30 mg, esomeprazole 20 mg, or rabeprazole 20 mg) for 4-8 weeks 6, 4
• PPIs are more effective than ranitidine and misoprostol in preventing NSAID ulcer recurrence and improving overall symptom control 2
• For severe gastritis with ulceration, higher dose regimens may be needed (omeprazole 40 mg, lansoprazole 60 mg, or rabeprazole 40 mg daily) 6

Gastroprotection in Patients Continuing NSAIDs

• PPI therapy is the rational choice for gastroprotection in patients who must continue NSAID use 2
• H. pylori eradication should be performed before starting NSAID treatment and is mandatory in patients with a peptic ulcer history 1
• Combining a PPI with NSAIDs reduces the rate of endoscopic NSAID-related ulcers by 90% 2

Second-Line Treatment After First-Line Failure

After failure of bismuth quadruple therapy, levofloxacin-based triple therapy is recommended (if no prior fluoroquinolone exposure), consisting of PPI twice daily, amoxicillin 1000 mg twice daily, and levofloxacin 500 mg once daily for 14 days. 1

Critical Considerations for Second-Line Therapy

• Never repeat antibiotics that failed previously, especially clarithromycin and levofloxacin, where resistance develops rapidly after exposure 1, 2
• After two failed eradication attempts with confirmed patient adherence, antibiotic susceptibility testing should guide further treatment 1, 2

Third-Line and Rescue Therapies

• Rifabutin-based triple therapy (rifabutin 150 mg twice daily, amoxicillin 1000 mg twice daily, PPI twice daily) for 14 days 1, 2
• High-dose dual amoxicillin-PPI therapy (amoxicillin 2-3 grams daily in 3-4 split doses, high-dose PPI twice daily) for 14 days 1

Confirmation of H. pylori Eradication

Test for eradication success at least 4 weeks after completion of therapy using urea breath test or validated monoclonal stool antigen test, and discontinue PPI at least 2 weeks before testing. 1

• Never use serology to confirm eradication—antibodies may persist long after successful treatment 1

Common Pitfalls to Avoid

• Do not use standard-dose PPI once daily—always use high-dose twice-daily PPI for H. pylori eradication 1
• Avoid pantoprazole as it has significantly lower potency (40 mg pantoprazole = 9 mg omeprazole equivalents) 2
• Do not assume low clarithromycin resistance without local surveillance data—most regions now have high resistance rates 1
• Avoid concomitant, sequential, or hybrid therapies as they include unnecessary antibiotics that contribute to global antibiotic resistance 1, 2
• Do not use levofloxacin as first-line therapy—the FDA recommends fluoroquinolones be used as a last choice due to risk of serious side effects 2, 1

Patient Factors Affecting Treatment Success

• Smoking increases the risk of eradication failure (odds ratio of 1.95 for smokers versus non-smokers) 1, 7
• High BMI increases risk of failure due to lower drug concentrations at the gastric mucosal level 1
• Patient compliance is critical—more than 10% of patients are poor compliers, leading to much lower eradication rates 1
• Diarrhea occurs in 21-41% of patients during the first week of H. pylori eradication therapy—consider adjunctive probiotics to reduce this risk and improve compliance 1