Influence of 1-week Helicobacter pylori eradication therapy with rabeprazole, clarithromycin, and metronidazole on 13C-aminopyrine breath test

Helicobacter pylori eradication therapy is commonly prescribed in the general population. Treatment consists of drugs that are mainly metabolized by the liver cytochrome P-450 (CYP) enzymatic pool. Most H. pylori-infected patients often take drugs for comorbid illnesses, therefore increasing the potential for drug-drug interactions. We aimed to evaluate the interactions of rabeprazole, clarithromycin, and metronidazole 1-week H. pylori eradication therapy with CYP-dependent liver metabolic function in clinical practice. Ten patients referred to our unit for H. pylori infection underwent 1-week eradication therapy with rabeprazole (20 mg, b.i.d.), clarithromycin (500 mg, b.i.d.), and metronidazole (500 mg, b.i.d.). We chose the C-13-aminopyrine breath test (C-13-ABT) to evaluate CYP-dependent liver function since it is noninvasive and nonharmful. All patients underwent C-13-ABT at three time points: before therapy (to), at the end of therapy (t(8)), and after 1 month of follow-up (t(38)). Mean C-13-ABT dose/hr (t(0) = 14.0 +/- 5.4, t(8) = 13.5 +/- 4.0, t(38) = 16.1 +/- 5.6) as well as C-13-ABT cumulative dose (t(0) = 2.4 +/- 1.1, t(8) = 2.4 +/- 0.8, t(38) = 2.6 +/- 1.0) were not statistically different at the three time points of the study. These results did not seem to be influenced by drugs being administered concomitantly. In everyday clinical practice rabeprazole-based H. pylori eradication therapy does not seem to display any significant interactions with CYP-dependent liver function, even in patients on multiple drugs.