Effect of genetic differences in omeprazole metabolism on cure rates for Helicobacter pylori infection and peptic ulcer

Ann Intern Med. 1998 Dec 15;129(12):1027-30. doi: 10.7326/0003-4819-129-12-199812150-00006.


Background: Omeprazole is metabolized by S-mephenytoin 4'-hydroxylase (CYP2C19) in the liver. In persons with a poor-metabolizer genotype for CYP2C19, the therapeutic efficacy of omeprazole may be increased.

Objective: To investigate whether CYP2C19 genotype status is associated with cure rates for Helicobacterpylori infection and peptic ulcer achieved by using dual therapy with omeprazole and amoxicillin.

Design: Prospective cohort study.

Setting: University hospital and health service center in Hamamatsu, Japan.

Patients: 62 patients with peptic ulcer and H. pylori infection.

Intervention: Omeprazole and amoxicillin.

Measurements: CYP2C19 genotype status and cure rates for H. pylori infection and peptic ulcer.

Results: Cure rates for H. pylori infection were 28.6% (95% CI, 13.1% to 48.7%), 60% (CI, 38.6% to 83.0%), and 100% (CI, 66.4% to 100%) in the rapid-, intermediate-, and poor-metabolizer groups, respectively. Healing rates for both duodenal and gastric ulcer in the three groups were roughly parallel with cure rates for H. pylori infection.

Conclusion: The results of the genotyping test for CYP2C19 seem to predict cure of H. pylori infection and peptic ulcer in patients who receive dual therapy with omeprazole and amoxicillin.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Amoxicillin / therapeutic use
  • Anti-Ulcer Agents / pharmacokinetics*
  • Anti-Ulcer Agents / therapeutic use
  • Aryl Hydrocarbon Hydroxylases*
  • Cytochrome P-450 CYP2C19
  • Cytochrome P-450 Enzyme System / genetics
  • Cytochrome P-450 Enzyme System / metabolism
  • Drug Therapy, Combination
  • Female
  • Genotype
  • Helicobacter Infections / drug therapy
  • Helicobacter Infections / genetics
  • Helicobacter Infections / metabolism*
  • Helicobacter pylori*
  • Humans
  • Liver / metabolism
  • Male
  • Middle Aged
  • Mixed Function Oxygenases / genetics
  • Mixed Function Oxygenases / metabolism
  • Omeprazole / pharmacokinetics*
  • Omeprazole / therapeutic use
  • Penicillins / therapeutic use
  • Peptic Ulcer / drug therapy
  • Peptic Ulcer / genetics
  • Peptic Ulcer / metabolism*
  • Phenotype
  • Prospective Studies


  • Anti-Ulcer Agents
  • Penicillins
  • Amoxicillin
  • Cytochrome P-450 Enzyme System
  • Mixed Function Oxygenases
  • Aryl Hydrocarbon Hydroxylases
  • CYP2C19 protein, human
  • Cytochrome P-450 CYP2C19
  • Omeprazole