Amoxicillin or Tetracycline in Bismuth-containing Quadruple Therapy As First-line Treatment for Infection

Aim: To compare the efficacy and safety between modified quadruple- and bismuth-containing quadruple therapy as first-line eradication regimen for infection.

Methods: This study was a multicenter, randomized-controlled, non-inferiority trial. Subjects endoscopically diagnosed with infection were randomly allocated to receive modified quadruple- (rabeprazole 20 mg bid, amoxicillin 1 g bid, metronidazole 500 mg tid, bismuth subcitrate 300 mg qid [elemental bismuth 480 mg]; PAMB) or bismuth-containing quadruple therapy (rabeprazole 20 mg bid, bismuth subcitrate 300 mg qid, metronidazole 500 mg tid, tetracycline 500 mg qid; PBMT) for 14 days. Rates of eradication success and adverse events were investigated. Antibiotic resistance was determined using the agar dilution and DNA sequencing of the clarithromycin resistance point mutations in the 23 S rRNA gene of .

Results: In total, 233 participants were randomized, 27 were lost to follow-up, and four violated the protocol. Both regimens showed an acceptable eradication rate in the intention-to-treat (PAMB: 87.2% vs. PBMT: 82.8%, = .37), modified intention-to-treat (96.2% vs. 96%, > .99), and per-protocol (96.2% vs. 96.9%, > .99) analyses. Non-inferiority in the eradication success between PAMB and PBMT was confirmed. The amoxicillin-, metronidazole-, tetracycline-, clarithromycin-, and levofloxacin-resistance rates were 8.3, 40, 9.4, 23.5, and 42.2%, respectively. Antimicrobial resistance did not significantly affect the efficacy of either therapy. Overall compliance was 98.1%. Adverse events were not significantly different between the two therapies.

Conclusion: Modified quadruple therapy comprising rabeprazole, amoxicillin, metronidazole, and bismuth is an effective first-line treatment for the infection in regions with high clarithromycin and metronidazole resistance.