Efficacy and safety of twice a day, bismuth-containing quadruple therapy using high-dose tetracycline and metronidazole for second-line Helicobacter pylori eradication.

We determined for the first time that twice a day intake of bismuth-containing quadruple therapy using 2 g/d of tetracycline, 1.5 g/d of metronidazole, and 600 mg/d of bismuth subcitrate for one week is effective and safe as the conventional four times a day therapy. Twice a day intake decreased abdominal pain, discomfort, and distention.