VARIABILITY WITH OMEPRAZOLE AMOXICILLIN COMBINATIONS FOR TREATMENT OFHELICOBACTER-PYLORI INFECTION

Objective: Although omeprazole co-therapy enhances the effectiveness o f some antimicrobials for the treatment of Helicobacter pylori infecti on, results have not been uniform. A meta-analysis suggested that 20 m g of omeprazole b.i.d. and 2 g or more of amoxicillin would yield a >8 0% success rate (Gastroenterology 1994;106: 142A). Our objective in th is study was to test that hypothesis. Methods: Volunteers with H. pylo ri infection were studied. Anti-H. pylori therapy was administered wit h meals for 14 days (omeprazole 20 mg b.i.d. plus amoxicillin 1 g t.i. d., or omeprazole 20 mg b.i.d, plus amoxicillin 0.5 g t.i.d.). Endosco py was performed 4-6 wk after antimicrobial therapy ended, and the pre sence or absence of H. pylori was determined with biopsy specimens by Genta stain. Results: Fifty-nine volunteers completed the study; 30 we re studied twice. The overall success for initial treatment with eithe r combination of amoxicillin and omeprazole was 18 of 59 [30.5%; 95% c onfidence interval (CI) = 19-44%]. The success rate with 500 mg amoxic illin t.i.d. was 7 of 29 (24%; 95% CI = 10-43%). With 1 g t.i.d. amoxi cillin, the cure rate was higher (36.6%) (11 of 30; 95% CI = 20-56%), or intention-to-treat result was 11 of 31 (35.4%), which includes the early dropout. Compliance was >95% for both therapies. Side effects we re experienced by eight patients, two receiving 1.5 g amoxicillin and six receiving 3 g amoxicillin (p > 0.2). German trials suggest that be tter results might be achieved when amoxicillin is given as suspension while fasting. Thirty treatment failures were re-treated with 1 g amo xicillin suspension t.i.d., given fasting, and omeprazole 20 mg b.i.d. The cure rate was 16.6% (95% CI = 6-35%). Conclusion: Amoxicillin/ om eprazole combinations for treatment of H. pylori infection do not yiel d consistent results. The reason is unknown, but the reported high rat e of success with 40 mg of omeprazole and 750 mg t.i.d. suggests that almost complete inhibition of acid secretion is necessary to obtain co nsistent results with this combination.