Influence of smoking and CYP2C19 genotypes on H-pylori eradication success

CYP2C19 polymorphisms and smoking influence the efficacy of H. pylori eradication therapy, but interaction between the two have hitherto not been examined. A total of 142 H. pylori-positive patients who received triple drug therapy with lansoprazole, amoxicillin and clarithromycin were categorized into three groups with regard to diplotypes of CYP2C19: homozygous extensive metabolizer (homEM), heterozygous EM (hetEM), and poor metabolizer (PM). The overall success rate was 61 center dot 3%. Smoking was an independent risk factor of eradication failure (OR 2 center dot 81, 95% CI 1 center dot 14-6 center dot 91), whereas CYP2C19 polymorphisms were less influential. Among non-smokers, the homEM and hetEM groups showed worse eradication rates (58 center dot 5 and 67 center dot 3%) relative to PM (76 center dot 2%) as expected; however, an opposite trend was observed among smokers (homEM 50-0%, hetEM 46 center dot 7%, PM 20 center dot 0%), indicating possible interactions with CYP2C19 polymorphisms. Smoking has a greater influence on H. pylori eradication than the CYP2C19 genotype. Interaction between smoking and CYP2C19 should be examined in the future.