H. Pylori Quadruple Therapy Dosages
Bismuth quadruple therapy consists of: PPI (standard dose) twice daily, bismuth subsalicylate ~300 mg four times daily, metronidazole 500 mg three to four times daily, and tetracycline 500 mg four times daily for 14 days. 1
Standard Bismuth Quadruple Therapy Regimen
The precise dosing for bismuth quadruple therapy is as follows:
- Proton Pump Inhibitor: Standard dose twice daily (pantoprazole 40 mg, lansoprazole 30 mg, omeprazole 20 mg, esomeprazole 20 mg, dexlansoprazole 30 mg, or rabeprazole 20 mg) 1
- Bismuth subsalicylate: Approximately 300 mg four times daily 1
- Metronidazole: 500 mg three to four times daily (or 400 mg four times daily per some protocols) 1
- Tetracycline: 500 mg four times daily 1
- Duration: 14 days is preferred, though 10-14 days is acceptable if 10 days has been proven locally effective 1
Alternative Quadruple Therapy: Concomitant Non-Bismuth Regimen
When bismuth is unavailable, concomitant non-bismuth quadruple therapy is the recommended alternative:
- PPI: Standard dose twice daily 1
- Amoxicillin: 1000 mg (1 gram) twice daily 1
- Clarithromycin: 500 mg twice daily 1
- Metronidazole: 500 mg twice daily 1
- Duration: 14 days (10-14 days acceptable) 1
Critical Dosing Considerations
PPI dosing timing is crucial: All PPIs should be administered 30 minutes prior to eating or drinking on an empty stomach, without concomitant use of other antacids such as H2-receptor antagonists. 1
High-dose PPI increases efficacy: Using double the standard PPI dose (e.g., esomeprazole or rabeprazole 40 mg twice daily instead of 20 mg) can increase eradication rates by 8-12%, particularly when using second-generation PPIs. 1, 2
Metronidazole dosing flexibility: Higher doses of metronidazole (1.5-2 grams daily in divided doses) may improve eradication rates even against resistant strains when combined with bismuth. 3
Treatment Duration Rationale
14 days is superior to shorter durations: Extending treatment from 7 to 10-14 days improves eradication success by approximately 5%. 1, 2 The Toronto Consensus recommends 14 days for all first-line treatments to maximize the probability of succeeding on the first attempt. 1
Common Pitfalls to Avoid
Do not use standard-dose PPI once daily: This is inadequate for H. pylori eradication—always use twice-daily dosing to maximize gastric pH elevation. 3, 2
Avoid underdosing metronidazole: The four-times-daily dosing of metronidazole (500 mg QID) is critical for bismuth quadruple therapy efficacy, even though three-times-daily dosing (500 mg TID) is sometimes listed as acceptable. 1
Ensure proper tetracycline formulation: Use tetracycline HCl specifically, as this is the formulation with proven efficacy against H. pylori. 3
Patient compliance is critical: More than 10% of patients are poor compliers with quadruple therapy due to the complex four-times-daily dosing schedule, which significantly reduces eradication rates. 3 Counsel patients extensively about the importance of completing the full 14-day course with all medications taken as prescribed.