What are the recommended dosages for H pylori (Helicobacter pylori) treatment?

H. pylori Treatment with Dosages

Bismuth quadruple therapy for 14 days is the recommended first-line treatment, consisting of a PPI twice daily, bismuth 300mg four times daily, metronidazole 500mg three to four times daily (total 1.5-2g/day), and tetracycline 500mg four times daily. 1

First-Line Treatment Regimen

Bismuth Quadruple Therapy (14 days):

• PPI twice daily - taken 30 minutes before meals on an empty stomach 1

  • Standard options: pantoprazole 40mg, lansoprazole 30mg, omeprazole 20mg, esomeprazole 20mg, dexlansoprazole 30mg, or rabeprazole 20mg 1
  • Preferred PPIs: esomeprazole or rabeprazole 40mg twice daily increase cure rates by an additional 8-12% 1, 2

• Bismuth subsalicylate 262mg (or bismuth subcitrate 120mg) four times daily 1

• Metronidazole 500mg three to four times daily (total daily dose 1.5-2g) 1

• Tetracycline 500mg four times daily 1

This regimen achieves 80-90% eradication rates even against metronidazole-resistant strains due to bismuth's synergistic effect, and is not affected by clarithromycin resistance 1, 2, 3.

Alternative First-Line Regimen (When Bismuth Unavailable)

Concomitant Non-Bismuth Quadruple Therapy (14 days):

• PPI twice daily (high-dose preferred) 2
• Amoxicillin 1000mg twice daily 2, 4
• Clarithromycin 500mg twice daily 2, 4
• Metronidazole 500mg twice daily 2

This regimen should only be used in areas with documented clarithromycin resistance <15%, as resistance now exceeds 15-20% in most of North America and Europe 2, 3.

Second-Line Treatment After First-Line Failure

If clarithromycin-based therapy fails, use bismuth quadruple therapy (if not previously used) for 14 days with dosages as above 1.

If bismuth quadruple therapy fails, use levofloxacin triple therapy (14 days):

• PPI twice daily (high-dose) 1
• Amoxicillin 1000mg twice daily 1, 4
• Levofloxacin 500mg once daily OR 250mg twice daily 1

Critical caveat: Do not use levofloxacin empirically as first-line therapy due to rapidly rising fluoroquinolone resistance rates (11-30% primary, 19-30% secondary) 2, 3.

Third-Line and Rescue Therapies

Rifabutin Triple Therapy (14 days):

• PPI twice daily (high-dose) 1
• Amoxicillin 1000mg twice daily 1, 4
• Rifabutin 150mg twice daily OR 300mg once daily 1, 2

High-Dose Dual Therapy (14 days):

• Amoxicillin 2-3 grams daily in 3-4 split doses 1
• PPI high-dose twice daily 1

Critical Optimization Factors

Treatment duration must be 14 days - this is superior to 7-10 day regimens and improves eradication rates by approximately 5% 1, 2, 3.

PPI dosing is mandatory twice daily, taken 30 minutes before meals on an empty stomach, without concomitant use of other antacids 1, 2. Standard once-daily dosing is inadequate and reduces efficacy by 6-10% 2, 3.

Antibiotic reuse rules:

• Never reuse clarithromycin or levofloxacin - resistance develops rapidly after exposure 1, 2, 3
• Can reuse amoxicillin and tetracycline - resistance remains rare (<5%) 1, 2, 3
• Can reuse metronidazole with bismuth - bismuth's synergistic effect overcomes in vitro resistance 1, 3

Special Populations

Penicillin allergy: Bismuth quadruple therapy is the first choice, as it contains tetracycline instead of amoxicillin 1, 3.

Severe renal impairment (GFR <30 mL/min):

• Do NOT use amoxicillin 875mg dose 4
• GFR 10-30 mL/min: amoxicillin 500mg or 250mg every 12 hours 4
• GFR <10 mL/min: amoxicillin 500mg or 250mg every 24 hours 4
• Hemodialysis: amoxicillin 500mg or 250mg every 24 hours, with additional dose during and at end of dialysis 4

After Two Failed Attempts

Antibiotic susceptibility testing should be obtained before attempting further treatment 1, 2, 3. Molecular testing for clarithromycin and levofloxacin resistance can guide therapy selection earlier in the algorithm 1, 2.

Verification of Eradication

Confirm eradication with urea breath test or monoclonal stool antigen test:

• At least 4 weeks after completing therapy 1, 2, 3
• At least 2 weeks after stopping PPIs 1, 2, 3
• Never use serology - antibodies persist long after successful treatment 2, 3

Common Pitfalls to Avoid

Never assume low clarithromycin resistance without local surveillance data - most regions now have high resistance rates exceeding 15-20% 2, 3.

Avoid standard-dose PPI once daily - always use twice-daily dosing to maximize gastric pH elevation 2.

Do not use concomitant, sequential, or hybrid therapies - they include unnecessary antibiotics that contribute to global antibiotic resistance without therapeutic benefit 2.

Patient factors affecting success: Smoking increases eradication failure risk (OR 1.95), high BMI leads to lower drug concentrations at gastric mucosal level, and poor compliance (>10% of patients) significantly reduces eradication rates 2.