Standard Triple Therapy for H. pylori:

Oral twice-daily doses of rabeprazole (20 mg), amoxicillin (1 g) and clarithromycin (500 mg)

One of two treatments randomly assigned to treatment naive participants in Aklavik

Sequential Therapy for H. pylori:

Oral twice-daily doses of rabeprazole (20 mg) and amoxicillin (1 g) on days 1-5, and on days 6-10, rabeprazole (20 mg), metronidazole (500 mg) and clarithromycin (500 mg)

One of two treatments randomly assigned to treatment naive participants in Aklavik, Old Crow, Tuktoyaktuk & Fort McPherson

Quadruple Thearpy for H. pylori:

Oral doses of rabeprazole (20 mg) twice daily, metronidazole (500 mg) three times daily, bismuth subsalicylate (Pepto-Bismol) (2 tablets) four times daily and tetracycline (500 mg) four times daily

One of two treatments randomly assigned to treatment naive participants in Old Crow, Tuktoyaktuk & Fort McPherson

Sequential Therapy for H. pylori:

Oral twice-daily doses of rabeprazole (20 mg) and amoxicillin (1 g) on days 1-5, and on days 6-10, rabeprazole (20 mg), metronidazole (500 mg) and clarithromycin (500 mg)

One of two treatments randomly assigned to participants who previously failed one or more treatments in Aklavik, Old Crow, Tuktoyaktuk & Fort McPherson

Oral twice-daily doses of rabeprazole (20 mg), amoxicillin (1 g) and clarithromycin (500 mg)

Treatment effectiveness, defined as the probability (average risk) of elimination of H. pylori infection following treatment, measured as the proportion of trial participants with a negative post-treatment urea breath test at least 10 weeks following completion of treatment. Using an intention-to-treat analysis, the denominator for this proportion is the number of trial participants assigned treatment. Using a per-protocol analysis, the denominator for this proportion is the number of trial participants who completed treatment and were tested post-treatment.

Participants are administered a urea breath test using 13C-labeled urea dissolved in a citric acid solution. We use the following test value classifications for determining the outcome:

>=4.0 (Positive for H. pylori infection) Between 2.5 and 4.0 (Borderline; repeat test) Between 2.4 and -1.99 (Negative for H. pylori infection) Less than -2.0 (Uncertain test result, repeat test)

Participants are asked to return blister packs with unused medication so skipped doses can be counted. Participants are also interviewed to obtain details about their adherence to the regimen.

Participants are contacted by telephone during the completion of the treatment regimen and asked if they have experienced adverse effects. Participants are also interviewed immediately after the completion of treatment and asked if they experienced adverse effects during the completion of treatment.