What is the recommended treatment regimen for H pylori, specifically the PCAB (Proton pump inhibitor, Clarithromycin, Amoxicillin, and Bismuth) therapy?

Recommended Treatment Regimen for H. pylori (PCAB Therapy)

The recommended PCAB (Proton pump inhibitor, Clarithromycin, Amoxicillin, and Bismuth) therapy for H. pylori eradication is a 14-day regimen consisting of a standard dose PPI twice daily, clarithromycin 500 mg twice daily, amoxicillin 1000 mg twice daily, and bismuth subsalicylate 120-140 mg three to four times daily. 1, 2, 3

Components and Dosing

• Proton Pump Inhibitor (PPI): Standard dose twice daily (e.g., esomeprazole 20 mg, rabeprazole 20 mg, omeprazole 20 mg, lansoprazole 30 mg, pantoprazole 40 mg, or dexlansoprazole 30 mg) 3
• Clarithromycin: 500 mg twice daily 1
• Amoxicillin: 1000 mg twice daily 1, 4, 5
• Bismuth: 120-140 mg (or 262 mg depending on formulation) three to four times daily 2, 3

Duration of Treatment

• The Toronto Consensus recommends 14 days for all first-line treatments to maximize eradication rates 1
• The Maastricht V/Florence Consensus agrees with 14 days, unless 10 days has been proven locally to be equally effective 1
• The American College of Gastroenterology (ACG) recommends 14 days for PPI triple therapy but considers 10-14 days adequate for bismuth quadruple therapy 1

Rationale and Efficacy

• This regimen is particularly recommended in areas with high clarithromycin resistance (>15-20%) 2
• The addition of bismuth significantly improves treatment efficacy, especially in the presence of metronidazole resistance 2
• Bismuth quadruple therapy is favored because it has acceptable success even against strains displaying in vitro metronidazole resistance 1
• Recent studies show eradication rates of 97.6% with bismuth-based quadruple regimens 6

Administration Guidelines

• Take PPI and amoxicillin 30 minutes before meals on an empty stomach 3, 5
• Amoxicillin should be taken at the start of a meal to minimize gastrointestinal intolerance 5
• Avoid concomitant use of other antacids such as H2-receptor antagonists 3
• Complete the full course of treatment to maximize eradication rates 3

Alternative Regimens

• If clarithromycin resistance is suspected (previous macrolide exposure or high local resistance rates), consider using bismuth quadruple therapy with tetracycline instead of clarithromycin (PPI, bismuth, metronidazole, tetracycline) 1, 2
• For patients with penicillin allergy, bismuth quadruple therapy with tetracycline is preferred (PPI, bismuth, metronidazole, tetracycline) 2, 3
• After failure of a clarithromycin-containing therapy, consider bismuth quadruple therapy or levofloxacin-based triple therapy 1, 2

Important Considerations

• Doxycycline should not be substituted for tetracycline in bismuth quadruple therapy due to inferior results 2
• After two failed therapies with confirmed patient adherence, H. pylori susceptibility testing should be considered to guide further treatment 1
• The choice of PPI is important, with rabeprazole and esomeprazole being preferred over pantoprazole due to their higher potency 2
• Compliance is a critical factor affecting H. pylori eradication success 7

Monitoring and Follow-up

• Confirm eradication at least 4 weeks after completing therapy 8
• Avoid antibiotics and PPIs for at least 2 weeks before testing for eradication 1
• Consider local antibiotic resistance patterns when selecting therapy 1, 3