IngentaConnect Omeprazole and CYP2C19 polymorphism: effects of long-term treatme...

Abstract:

Background:

The polymorphic enzyme CYP2C19 is of importance for the metabolism and effects of omeprazole during short-term treatment. Aim:

To investigate the relationship between CYP2C19 genotype and the effects of long-term omeprazole treatment. Material and methods:

A total of 180 patients with acid related disorders were genotyped for wild type and mutated CYP2C19 alleles by allele-specific PCR amplification. Gastrin and chromogranin A were assessed by radioimmunoassays, and pepsinogen I and H. pylori serology were assessed by ELISA methods. Results:

In 108 of the patients, who received a single dose of 20 mg omeprazole, there was no difference in gastrin and chromogranin A concentrations between the three CYP2C19 genotypes. In 72 patients on long-term treatment (> 1 year) with 20 mg omeprazole daily, serum gastrin as well as plasma chromogranin A concentrations (mean ± s.e.) were both about threefold higher in the wild type/mutated (52.1 ± 7.6 pMand 7.3 ± 1.3 nM(n=19), respectively) compared to wild type/wild type (14.7 ± 0.9 pMand 2.5 ± 0.1 nM(n=52), respectively; both comparisons P=0.0001). In a single mutated/mutated patient on long-term treatment, both gastrin and chromogranin A were high (88 pMand 13.7 nM, respectively). Serum pepsinogen I concentration was significantly lower in wild type/mutated (n=19) patients on long-term treatment, compared with the corresponding wild type/wild type (n=49) group (147 ± 19 μg/L vs. 193 ± 12 μg/L, P=0.04). Conclusion:

Patients with one (and probably also with two) mutated CYP2C19 allele(s) on long-term treatment with omeprazole had significantly affected serum gastrin and pepsinogen I and plasma chromogranin A concentrations compared with patients with two normal alleles. This indicates that changes in gastric mucosal morphology during omeprazole treatment might be dependent upon the degree of the individual's capacity to metabolize omeprazole.

Document Type: Research article

DOI: 10.1046/j.1365-2036.2000.00835.x

Affiliations: 1: Center of Gastroenterology, Departments of Surgery and Medicine, Clinical Research Center, Sweden 2: Department of Medical Laboratory Sciences and Technology, Division of Clinical Pharmacology at Karolinska Institute, Huddinge Hospital, Sweden 3: Department of Clinical Chemistry, Uppsala University Hospital, Uppsala, Sweden 4: Department of Surgery, Ersta Hospital, Sweden 5: Department of Biomedicine and Surgery, Division of Cell Biology, Linköping University Hospital, Linköping, Sweden

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Omeprazole and CYP2C19 polymorphism: effects of long-term treatment on gastrin, pepsinogen I, and chromogranin A in patients with acid related disorders