For Helicobacter pylori (H. pylori) management, Minocycline/Metronidazole quadruple treatment was not inferior to traditional quadruple therapy in intention-to-treat (ITT), modified intention-to-treat (mITT), and per-protocol (PP) analyses and can be utilized as an alternate therapy in populations having high levels of Metronidazole resistance. In this multicenter, randomized controlled trial, Minocycline and Tetracycline were compared for their effectiveness and tolerability profile in Bismuth-containing quadruple therapy for H. pylori rescue treatment.

Refractory H. pylori-infected patients (n = 368) with multiple treatment failures were randomized (1:1) to either the Minocycline group (Esomeprazole 20 mg twice daily, Bismuth 220 mg  twice daily plus Metronidazole 400 mg four times a day and Minocycline 100 mg twice daily) or the Tetracycline group (Tetracycline 500 mg four times a day).

The major endpoint was the rate of H. pylori eliminated as determined by a 13C-urea breath test at least six weeks following the completion of the treatment. The E test technique was used to determine antibiotic resistance. The eradication rates in the Minocycline group and Tetracycline group as per ITT, PP, and mITT analysis are depicted in Table 1:

The rates of resistance to Minocycline, Tetracycline, and Metronidazole were 0.7%, 1.4%, and 89.6%, respectively. Non-inferiority of Minocycline was substantiated. Resistance to Metronidazole had no impact on the effectiveness of either treatment. Similar frequencies of adverse events occurred with both treatments (55.4% vs. 53.3%), and nearly half of them were mild.

The most frequent side effect in the Minocycline group was dizziness. Regardless of Metronidazole resistance, Minocycline can be used as a substitute for Tetracycline in Bismuth-containing quadruple therapy for H. pylori elimination. It is important to emphasize the relatively high occurrence of adverse events in both regimens.