Direct comparisons of bismuth and proton pump inhibitor (PPI)-based triple and quadruple therapies for Helicobacter pylori eradication are lacking.
- metronidazole = 53%
- clarithromycin = 8%
Therefore, a research team in the latest issue of Gastroenterology have conducted a randomized study to address this.
The research team allocated infected dyspeptic patients to 1 of 3 treatment regimes:
- pantoprazole 40 mg, amoxicillin 1000 mg, and clarithromycin 500 mg, all twice daily, for 7 days (PAC7)
- pantoprazole 40 mg twice daily, bismuth subcitrate 108 mg, and tetracycline 500 mg, both 4 times daily, and metronidazole 200 mg 3 times daily and 400 mg at night for 7 days (PBTM7)
- bismuth subcitrate 108 mg and tetracycline 500 mg, both 4 times daily, and metronidazole 200 mg 3 times daily and 400 mg at night for 14 days (BTM14)
The team assessed the treatment outcome using a 13C-urea breath test.
The researchers found that eradication rates (intention to treat [n = 405]/per protocol [n = 320]) were similar for PAC7 (78%/82%) and PBTM7 (82%/88%).
PBTM7 was also found to be significantly superior to BTM14 (69%/74%).
In addition, the team found pretreatment metronidazole resistance (MR) to be 53% and clarithromycin resistance 8%.
They also determined eradication rates for primary metronidazole sensitive/resistant isolates were 74%/87% with PAC7 and 80%/81% for PBTM7, compared with 76%/55% for BTM14.
Noncompliance was found to be greater with BTM14 (15%) than PAC7 (3%) or PBTM7 (6%).
Furthermore, moderate-severe adverse events were more common with BTM14 (45%), than PAC7 (23%) or PBTM7 (25%) with more discontinuations (9%, 2%, 3%, respectively).
Dr Peter Katelaris's team concluded, "1-week PPI triple therapy is well tolerated and effective".
"The addition of PPI to bismuth triple therapy allows reduction of treatment duration with improved efficacy and tolerability, despite a high rate of MR."
"Quadruple therapy appears to overcome pretreatment MR in most cases."
"2-week bismuth triple therapy is significantly inferior to quadruple therapy and less well tolerated than both 1-week therapies."