Is a long-term ranitidine-based triple therapy against Helicobacter pylori only a heritage of the past? A prospective, randomized clinicopharmacological study

SUMMARY Background: Acid suppression plus two antibiotics is currently considered the gold standard anti-Helicobacter pylori treatment, but the effective role of gastric antisecretory drugs is still poorly understood. Aims: To compare a 14-day ranitidine-based triple regimen against Helicobacter pylori with one based on omeprazole, and to study the influence of antisecretory drugs on metronidazole pharmacokinetics in human plasma. Methods: A total of 150 dyspeptic H. pylori-infected patients were randomized for ranitidine 300 mg b.d. (RCM group) or omeprazole 20 mg b.d. (OCM group) 14-day triple therapy, with clarithromycin 500 mg b.d. and metronidazole 500 mg b.d. On the eighth day of therapy, metronidazole pharmacokinetics was studied in plasma by high-performance liquid chromatography. The pharmacokinetic parameters (terminal half-life, area under the curve, peak-plasma level, peak time) of metronidazole were computed using standard noncompartmental methods. H. pylori status was monitored before and 4 weeks after the end of therapy by histology, serology and rapid urease test. Results: On an intention-to-treat basis, eradication rates were 91 and 76% for the RCM and OCM groups respectively (P < 0.02). Significantly different pharmacokinetic parameters of metronidazole were found between the groups: peak-plasma level (P < 0.01) and area under the curve (P < 0.02). Conclusion: Our results show that the RCM regimen was more effective than that based on OCM and that the antisecretory drugs affected metronidazole availability, increasing the efficacy of ranitidine-based regimens.