omeprazole, Prilosec
The usefulness of a structured questionnaire in the assessment of symptomatic gastroesophageal reflux disease.

Carlsson R, Dent J, Bolling-Sternevald E, Johnsson F, Junghard O, Lauritsen K, Riley S, Lundell L.

Dept. of Surgery, Sahlgren's University Hospital, Goteborg, Sweden.

BACKGROUND: The diagnosis of gastroesophageal reflux disease (GERD) rests primarily on recognition of symptom patterns that are classical for reflux disease, but little attention has been paid to the use of a formal questionnaire for identifying such symptom patterns. METHODS: A self-administered questionnaire was developed which has seven items that focus on the nature of the symptoms and the precipitating, exacerbating, and relieving factors. The diagnostic validity of the questionnaire was tested against endoscopy and 24-h pH monitoring. A further evaluation was undertaken in patients with symptoms suggestive of GERD and in patients with non-ulcer dyspepsia, to identify factors that might predict symptom relief during treatment with omeprazole. RESULTS: When endoscopic esophageal mucosal breaks and 24-h pH data were used as criteria for the diagnosis of GERD, the questionnaire had a sensitivity of 92% but a very low specificity of 19%. Symptom relief during treatment with omeprazole was predicted by the presence of heartburn, described as 'a burning feeling rising from the stomach or lower chest up towards the neck' (P = 0.004), and 'relief from antacids' (P = 0.02). In non-ulcer dyspepsia a positive response to omeprazole was confined to the subgroup of patients who identified their main discomfort as heartburn as described above. CONCLUSION: The present questionnaire using descriptive language usefully identified heartburn in patients presenting with upper abdominal symptoms, and this symptom predicted symptom resolution during treatment with omeprazole.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9829354&dopt=Abstract omeprozole Prilosec



omeprazole, Prilosec
CYP2C19 genotype and phenotype determined with omeprazole in patients with acid-related disorders with and without Helicobacter pylori infection.

Sagar M, Seensalu R, Tybring G, Dahl ML, Bertilsson L.

Dept. of Surgery, Clinical Research Center, Karolinska Institute, Huddinge Hospital, Sweden.

BACKGROUND: Omeprazole is to a major extent metabolized by cytochrome P450 isozyme CYP2C19. The aims of this study were to compare the phenotype of CYP2C19 determined by omeprazole with the genotype and to determine the effect of Helicobacter pylori infection on the metabolism of omeprazole. METHODS: One-hundred and forty-three Caucasian patients with acid-related disorders assessed with a combination of gastrointestinal symptoms and upper endoscopic findings were given 20 mg omeprazole orally. Three hours after intake, omeprazole and 5-hydroxyomeprazole plasma concentrations were determined with high-performance liquid chromatography, and the phenotype for metabolic capacity was expressed as metabolic ratio (MR). Genotyping of defect alleles (CYP2C19*2 and *3) was performed by polymerase chain reaction amplification. One hundred eleven patients were tested after the first dose of omeprazole and 32 patients after repetitive administration (median time, 30 days). H. pylori serology was determined with enzyme-linked immunosorbent assay at the time of phenotyping. RESULTS: Genotypically, 2.8% had two mutated alleles and were poor metabolizers (PM), and 22.4% were heterozygous extensive metabolizers (EM). Among the 111 patients who received the first omeprazole dose, 4 patients had MR >5--that is, belonged to the PM phenotype. Two of these had PM genotype (both CYP2C19*2/*2), and two had an EM genotype (CYP2C19*11*1 and *1/*3), indicating that they have still unidentified mutations. In the heterozygous EM group the mean MR was higher in patients who had been on continued omeprazole treatment than in those given the first dose (5.7 versus 2.5, P = 0.02). There were no significant differences in MR and omeprazole concentrations between H. pylori-negative (43%) and -positive (57%) patients. CONCLUSION: In all but two patients with probable unidentified mutations there was agreement between the CYP2C19 phenotype determined by omeprazole and the genotype. The metabolism of omeprazole in patients with acid-related disorders is genetically determined and without relation to H. pylori infection.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9829356&dopt=Abstract omeprozole Prilosec



omeprazole, Prilosec
Current or recent proton pump inhibitor therapy markedly impairs the accuracy of the [14C]urea breath test.

El-Nujumi A, Hilditch TE, Williams C, McColl KE.

University Department of Medicine and Therapeutics, Western Infirmary, Glasgow, UK.

BACKGROUND: There are increasing indications for assessing Helicobacter pylori status by non-invasive means in dyspeptic patients. There is also increasing use of proton pump inhibitor therapy for dyspeptic disease. AIMS: To determine the effect of proton pump inhibitor therapy on the accuracy of the [14C]urea breath test. PATIENTS: [14C]Urea breath tests were performed in 20 H. pylori-positive and 13 H. pylori-negative dyspeptic patients before commencing omeprazole and after 4 weeks of treatment with 40 mg/day and then 6 months of treatment with 20 mg/day. Further studies were done in H. pylori-positive patients to examine the time course of the onset and resolution of the effect observed. RESULTS: False negative results occurred in 45% of the H. pylori-positive subjects after 4 weeks of omeprazole 40 mg/day and in 28% after 6 months of 20 mg/day. False positive results occurred in 15% of the H. pylori-negative subjects after 4 weeks of omeprazole 40 mg/day. In the H. pylori-positive subjects time course studies showed increasing suppression of the breath test result over the first 2-4 weeks of treatment. It took a similar time for the breath test result to recover after stopping treatment. There was no significant change in H. pylori IgG serology in the H. pylori-positive patients after 7 months of omeprazole treatment. CONCLUSIONS: Proton pump inhibitor therapy markedly impairs the accuracy of the [14C]urea breath test and, in particular, produces a high proportion of false negative results. The effect is dose related and may persist for 2-4 weeks after stopping therapy. Patients should be carefully questioned about recent proton pump inhibitor therapy before accepting a negative breath test result as reliable.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9831270&dopt=Abstract omeprozole Prilosec



omeprazole, Prilosec
Antiulcer drug prescribing in hospital successfully influenced by "immediate concurrent feedback".

Kumana CR, Ching TY, Cheung E, Kong Y, Kou M, Chan CK, Chu KM, Seto WH, Lam SK.

Department of Medicine, University of Hong Kong, Hong Kong.

OBJECTIVE: To determine whether immediate concurrent feedback (ICF) focused on inpatient omeprazole prescribing achieved more rational and cost-effective antiulcer drug prescribing and usage. METHODS: In a 1400-bed teaching hospital, an audit (by specially trained personnel) was conducted to monitor inpatient prescribing of omeprazole (1) in preference to H2-antagonists and other drugs according to agreed criteria (Helicobacter pylori eradication, severe reflux esophagitis, rapid ulcer healing deemed urgent because of severe symptoms or complications, high-dose steroid therapy of > or =30 mg/day prednisolone) and (2) appropriateness of intravenous dosing (oral route not feasible or contraindicated). After baseline monitoring for 1 month, followed by relevant antiulcer drug therapy education, ICF was instituted for 1 year. This entailed explanatory memoranda requesting a change in prescribing issued to the respective medical teams of patients whose omeprazole prescription did not "conform." The main outcomes of the study were omeprazole prescription numbers per month and the proportion conforming, defined daily doses of antiulcer drugs used and corresponding expenditures, and pertinent antiulcer drug utilization data from 9 other local hospitals. RESULTS: Baseline omeprazole prescribing conformed in 32 of 173 (18%) of the patients compared with 451 of 546 (83%) during institution of ICF (P < 0001; chi2 test). Correspondingly, average overall omeprazole and ranitidine usage (inpatient and outpatient) and expenditure decreased (44% and 45%, respectively); collectively, use of less expensive alternatives increased about 61%. Estimated savings averaged about HK$150,000 ($20,000) per month. No comparable changes in usage were noted in 9 other local hospitals. CONCLUSION: Regarding hospital antiulcer drugs, this ICF strategy was associated with more rational prescribing and usage, and an important saving of resources.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9834050&dopt=Abstract omeprozole Prilosec



omeprazole, Prilosec
Evaluation of omeprazole genotoxicity in a battery of in vitro and in vivo assays.

Martelli A, Mattioli F, Mereto E, Brambilla Campart G, Sini D, Bergamaschi G, Brambilla G.

Department of Internal Medicine, University of Genoa, Italy.

Omeprazole, a proton pump inhibitor of wide use in the treatment of gastric acid-related disorders, was evaluated for its genotoxic effects in both rat and human cultured cells and in the intact rat. DNA repair synthesis, as revealed by autoradiography, was detected in primary cultures of metabolically competent rat hepatocytes exposed to concentrations ranging from 10 to 100 mg/l, but the responses cannot be considered as clearly positive. Under the same experimental conditions any significant evidence of DNA repair was absent in primary hepatocytes from two human donors. At the same concentrations a modest but dose-related increase of micronucleated cells, that reached the level of statistical significance at 33 mg/l, was present in primary rat hepatocytes and in one of two human donors. In human lymphocytes exposed to subtoxic concentrations ranging from 0.78 to 12.5 mg/l a reproducible concentration dependent clastogenic effect was absent. In partially hepatectomized female rats treated with a single p.o. dose of 1000 mg/kg, the frequency of micronucleated cells was 5.2-fold higher than in controls in the liver, but only 2.0-fold higher in polychromatic erythrocytes of the bone marrow. In rats of the same sex given azoxymethane as initiator of colon carcinogenesis the oral administration for 8 successive weeks of 10 mg/kg omeprazole on alternate days increased the response to azoxymethane, as indicated by the occurrence in colon mucosa of a modest but statistically significant increase in both the average number and size of aberrant crypt foci. Taken as a whole, our results suggest that omeprazole behaves as a weak genotoxic agent for the rat liver. Reliable information about the potential genotoxic risk to humans requires further studies on primary cells from a wide number of donors.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9846994&dopt=Abstract omeprozole Prilosec



omeprazole, Prilosec
Endogenous hypergastrinaemia does not promote growth of colonic mucosa or of a transplanted colon adenocarcinoma in rats.

Chen D, Destree M, Hakanson R, Willems G.

Department of Pharmacology, University of Lund, Sweden.

BACKGROUND/OBJECTIVE: Gastrin is trophic for the mucosa of the acid-producing part of the rat stomach, notably the histamine-producing ECL cells. Gastrin is said to stimulate growth also of colonic mucosa and colon cancer. The purpose of the present study was to examine whether endogenous hypergastrinaemia had trophic effects on normal colonic mucosa and transplanted colon adenocarcinoma in rats. METHODS: Rats were subjected to fundectomy (surgical removal of the acid-producing part of the stomach) or treatments known to induce endogenous hypergastrinaemia. The treatments included refeeding after 48 h of food deprivation or administration of omeprazole (400 micromol/kg/day, orally). Other operations included colostomy and sham operation. A K12-cell line, originally established from a 1,2-dimethylhydrazine-induced colon adenocarcinoma, was used for transplantation. The rates of cell proliferation were determined in the oxyntic and colonic mucosa and in the tumour by measuring the proportion of the cells that accumulated bromodeoxyuridine in their nuclei, i.e. the labelling index (LI). The thickness of the oxyntic mucosa and the activity of histidine decarboxylase (HDC), the histamine-forming enzyme of the ECL cells, were measured. In addition, the thickness of the colonic mucosa and the weight and volume of the tumour were measured. RESULTS: Refeeding or treatment with a single dose of omeprazole in fasted rats raised the serum gastrin concentration and the LI and HDC activity in the oxyntic mucosa; refeeding but not omeprazole raised the LI in the colonic mucosa. In fed rats, hypergastrinaemia induced by fundectomy or treatment with omeprazole (for 10 days) failed to affect either the LI or the thickness of the mucosa of the proximal colon and the excluded distal colon of the colostomized rats. Fundectomy failed to stimulate the growth of the tumour transplants. CONCLUSION: Endogenous hypergastrinaemia did not induce trophic effects on rat colonic mucosa and did not promote growth of a transplanted colon adenocarcinoma in the rat.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9855044&dopt=Abstract omeprozole Prilosec



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

Furuta T, Ohashi K, Kamata T, Takashima M, Kosuge K, Kawasaki T, Hanai H, Kubota T, Ishizaki T, Kaneko E.

Hamamatsu University School of Medicine and Honda Motor Co., Ltd., Japan. furuta akiha.hama-med.ac.jp

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.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9867757&dopt=Abstract omeprozole Prilosec



omeprazole, Prilosec
In vitro evaluation of dissolution properties and degradation products of omeprazole in enteric-coated pellets.

Storpirtis S, Rodrigues D.

Pharmacy Department, School of Pharmaceutical Sciences, University of Sao Paulo, Brazil.

This report describes results of an in vitro study in which capsules containing omeprazole in enteric-coated pellets from different Brazilian manufacturers were evaluated. The original product was the reference in comparison to three similar products (A, B, and C). Samples were submitted to severe conditions (40 degrees C and 75% relative humidity during 120 days), and the tests performed were the omeprazole content, the percentage of omeprazole dissolved from the pellets, and the amount of H 238/85, its main degradation product. The data obtained suggest that these products could not be considered interchangeable. Differences in physical and physicochemical properties of products A, B, and C indicated that they did not maintain the required stability and that bioavailability might be affected by the poor dissolution of omeprazole from the pellets.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9876567&dopt=Abstract omeprozole Prilosec