Personalized medicine for eradication of Helicobacter pylori

Regimens for eradication of Helicobacter pylori consist of a proton-pump inhibitor (PPI) and one or two antimicrobial agents, such as amoxicillin, clarithromycin or metronidazole. As the pharmacokinetics and pharmacodynamics of PPIs are affected by polymorphism of CYP2C19, doses and dosing schemes of a PPI should be optimized based on genotype status of each patient in order to yield higher eradication rates. PPIs affect the pharmacokinetics of other substrates of CYP2C19, such as warfarin and diazepam. Acid inhibition induced by a PPI also affects the pharmacokinetics of some drugs, such as itraconazole. Clarithromycin, one of the most frequently used antimicrobial agents in eradication of H. pylori, inhibits activity of CYP3A4, meaning that the pharmacokinetics of substrates of CYP3A4 are affected by clarithromycin. Therefore, clinicians must pay attention to the other drugs dosed to each of their patients. Therefore, the eradication regimen for H. pylori infection should be designed with the CYP2C19 genotype status, bacterial susceptibility to antimicrobial agents, and other drugs being taken by each patient having been taken into consideration.