Role of cytochrome P450 2C19 genetic polymorphisms in the therapeutic efficacy of omeprazole in Iranian patients with erosive reflux esophagitis.

Abstract

There are different clinical responses to omeprazole treatment in Iranian patients with gastroesophageal reflux disease. Omeprazole is metabolized in the liver by the cytochrome p450 2c19 (CYP2C19) enzyme. Two common polymorphisms of the CYP2C19 gene affect CYP2C19 enzyme activity. We investigated the effect of CYP2C19 gene polymorphisms on the clinical response to treatment with omeprazole in Iranian patients with erosive reflux esophagitis. Eighty-two Iranian patients with reflux esophagitis were enrolled in the study and underwent treatment with omeprazole at 40 mg daily for 4 weeks. A 2 mL sample of venous blood was obtained from each subject. CYP2C19 genetic polymorphisms were detected using the PCR-RFLP method. The patients were grouped into homo-extensive metabolizers and hetero-extensive metabolizers based on their CYP2C19 polymorphism. The grade of esophagitis was determined via endoscopy. The symptoms score was assessed at the beginning of treatment. Our results showed that the rate of complete clinical response to treatment with omeprazole was 95% in the hetero-extensive metabolizers group, which was higher than in the homo-extensive metabolizers group (P<0.001). CYP2C19 polymorphism influences the therapeutic efficacy of omeprazole in the treatment of Iranian patients with erosive reflux esophagitis. The clinical response and endoscopic healing of esophagitis are both affected by CYP2C19 genotype condition.