Background/aims: We previously investigated the effects of amoxicillin/omeprazole combined therapy on patients who were Helicobacter pylori (H. pylori) positive after gastrectomy for the treatment of gastric cancer, and we determined the difference in amoxicillin dosage between the therapeutic successes and failures. In the present study, assuming that amoxicillin dosage should be determined on the basis of body weight of each patient, we examined whether the eradication of H. pylori would be improved by using this novel dose-selection method.
Methodology: We have previously reported about eradication of H. pylori of remnant stomach as follows. Patients who underwent gastrectomy for the treatment of gastric cancer were enrolled if H. pylori was detected in their remnant stomach after the operation. Of these patients, 22 were treated with amoxicillin at 750 mg/day for 2 weeks and omeprazole at 20 mg/day for 8 weeks. For the evaluation of H. pylori eradication, endoscopic examination and 13C-urea breath test were performed 12 weeks after the initiation of the treatment. The amoxicillin dosage in the therapeutic successes was compared with that in the therapeutic failures, and we found that the dosage was 14.1 +/- 1.5 and 12.5 +/- 1.5 mg/kg/day in the successes and the failures, respectively. Following these results, another 10 H. pylori-positive patients were treated with amoxicillin greater than 16 mg/kg/day for 2 weeks and omeprazole at 20 mg/day for 8 weeks, and H. pylori eradication was evaluated as mentioned above. The efficacy of the drug therapy on H. pylori infection was compared between the two groups that one group (Group A) is treated with amoxicillin 750 mg/day for 2 weeks and omeprazole at 20 mg/day for 8 weeks and the other group (Group B) is treated with 1250 mg/day for 2 weeks and omeprazole at 20 mg/day for 8 weeks.
Results: The eradication rate of H. pylori in Group B (84.6%) was higher than that in Group A (42.1%). There was significant difference between the two groups (p = 0.028).
Conclusions: We assumed that the optimal dosage of amoxicillin was over 15.6 mg/kg/day for omeprazole-amoxicillin combined therapy for gastrectomized patients who were H. pylori positive, and the favorable therapeutic effects could be obtained by applying this amoxicillin dosage to the eradication of H. pylori.