Objective: To assess the efficacy of a 1-week course of omeprazole, clarithromycin and tinidazole for the eradication of Helicobacter pylori and the optimum dose of omeprazole required.
Design: The study was divided into two sequential phases. The first phase was an open, two-centre study. The second phase was a single-blind, single-centre study.
Methods: Patients found to be infected with H. pylori at endoscopy were enrolled in the study. In phase 1, patients were prescribed 20 mg omeprazole, 250 mg clarithromycin and 500 mg tinidazole twice daily for 1 week. In phase 2, all patients were prescribed 250 mg clarithromycin and 500 mg tinidazole twice daily for 1 week. In addition, patients were randomly assigned to receive 20 mg omeprazole twice daily (group A), 20 mg omeprazole daily (group B) or no omeprazole (group C). Eradication was assessed in all patients by 13C-urea breath testing 4 weeks after the completion of therapy.
Results: In phase 1, H. pylori eradication was achieved in 132 (88%) of 150 evaluable patients. In phase 2, eradication was achieved in 44 (88%) of 50 individuals in group A, 47 (88.7%) of 53 in group B and 30 (63.8%) of 47 in group C. In the omeprazole groups, 22 patients harboured metronidazole-resistant strains of H. pylori and all were cured by the omeprazole regimen. One patient harboured a strain of H. pylori that was resistant to clarithromycin alone but which was successfully eradicated. Treatment failed in two out of three patients harbouring H. pylori strains resistant to both clarithromycin and tinidazole.
Conclusion: One week of omeprazole, clarithromycin and tinidazole is effective in eradicating H. pylori. There is no advantage in increasing the dose of omeprazole from once to twice daily. This regimen is effective in patients with 5-nitroimidazole-resistant strains of H. pylori.