Influence of Helicobacter pylori eradication therapy on C-13 aminopyrine breath test: Comparison among omeprazole-, lansoprazole-, or pantoprazole-containing regimens

OBJECTIVE: Proton pump inhibitors and antimicrobial agents are widely used to eradicate Helicobacter pylori (H. pylori) infection. In the general popu lation the prevalence of infection and of polypharmacy increases the possib ility of drug-drug interactions during H. pylori eradication therapy. The p urpose of the present study was to assess the prevalence, degree, and clini cal relevance of metabolic interference with the cytochrome P450 enzymatic system occurring during 1 wk of administration of omeprazole, lansoprazole, or pantoprazole followed by the association of clarithromycin and metronid azole for another week. The C-13 aminopyrine breath test (ABT) was chosen t o screen for possible interactions. METHODS: We studied 30 patients referred to our Unit for H. pylori eradicat ion therapy. They were randomized to receive either omeprazole (20 mg b.i.d .), lansoprazole (30 mg b.i.d.), or pantoprazole (40 mg b.i.d.) for 2 wk. D uring the second week clarithromycin (250 mg b.i.d.) and metronidazole (500 mg b.i.d.) were added. ABT was performed before, and at the end of the fir st and second week of therapy. Percentage of the administered dose of C-13 recovered per hour at the peak (percent C-13 dose/h at the peak) and cumula tive percentage of administered dose of C-13 recovered over time at 120 min (percent C-13 dose cum(120)) were the ABT evaluated parameters. RESULTS: At baseline all patients showed a normal liver function. In indivi dual patients during treatment we observed various liver metabolic interact ions both as inhibition and induction, as well as after the first and the s econd week of therapy. However, mean modifications of the ABT parameters du ring the 2 weeks of therapy were not statistically significant compared to baseline values. None of the patients who had ABT variations complained of side effects. CONCLUSIONS: H. pylori eradication therapy interferes with cytochrome P450- dependent liver metabolic activity. However, the clinical relevance of thes e metabolic interactions is not yet apparent, and further investigation is needed. H. pylori eradication therapy appears safe, but these interactions should be considered in the choice of proton pump inhibitor and antimicrobi al agents. (Am J Gastroenterol 2000;95:2762-2767. (C) 2000 by Am. Coll. of Gastroenterology).