Seven-Day Bismuth-Based Quadruple Therapy as an Initial Therapy for Helicobacter pylori Infection in a High Metronidazole-Resistant Area

Abstract

Introduction: Metronidazole (MTZ) resistance is almost 50% in Thailand, which has limited the use of MTZ for eradication therapy. The aims of this study were to evaluate the efficacy and safety profiles of bismuth-based quadruple therapy including MTZ as a treatment for H. pylori infection in a high MTZ-resistant area. Methods: This was a prospective study where a total of 100 patients with non-ulcer dyspepsia and had active H. pylori infection received 7 days of quadruple therapy (pantoprazole 40 mg twice a day, bismuth subsalicylate 1,048 mg twice a day, amoxicillin 1 gm twice a day, and metronidazole 400 mg 3 times a day). H. pylori was defined as positive culture or 2 positive tests (CLO test and histology). Antibiotic susceptibility tests were also done. At least 2 weeks after treatment, 13 C urea breath test (13C-UBT) was performed to confirm H. pylori eradication. Results: A total of 100 patients was enrolled in this study, including 40 males and 60 females with mean age of 43 years. After 7 days of quadruple therapy, 13C-UBT was negative in 48/50 (96%) of MTZ sensitive group and 40/50 (80%) in MTZ-resistant group. Primary in vitro MTZ resistance was observed in 50% of patients. Minor adverse reactions such as nausea (10%) and metallic taste (10%) were found, and none of the patients dropped out because of these side effects. Conclusion: Initial treatment with 7-day bismuth-based quadruple therapy including MTZ and amoxycillin and pantoprazole is highly effective in MTZ-sensitive, while less effective in MTZ-resistant, H. pylori. Either longer duration or higher dose of MTZ might be preferred to improve H. pylori eradication in an area with high MTZ resistance.Figure 1: Eradication rates were 96% in MTZ-sensitive and 80% in MTZ-resistant groups.