CYP7A1 Gene Induction via SHP-Dependent or Independent Mechanisms can Increase the Risk of Drug-Induced Liver Injury Independently or in Synergy with BSEP Inhibition.

Drug-induced liver injury (DILI) is a frequent cause of clinical trial failures during drug development. While inhibiting bile salt export pump (BSEP) is a well-documented DILI mechanism, interference with genes related to bile acid (BA) metabolism and transport can further complicate DILI development. Here, the effects of twenty-eight compounds on genes associated with BA metabolism and transport were evaluated, including those with discontinued development or use, boxed warnings, and clean labels for DILI. The study also included rifampicin and omeprazole, pregnane X receptor and aryl hydrocarbon receptor ligands, and four mitogen-activated protein kinase kinase (MEK1/2) inhibitors. BSEP inhibitors with more severe DILI, notably pazopanib and CP-724714, significantly upregulated the expression of 7 alpha-hydroxylase (CYP7A1), independent of small heterodimer partner (SHP) expression. CYP7A1 expression was marginally induced by omeprazole. In contrast, its expression was suppressed by mometasone (10-fold), vinblastine (18-fold), hexachlorophene (2-fold), bosentan (2.1-fold), and rifampin (2-fold). All four MEK1/2 inhibitors that show clinical DILI were not potent BSEP inhibitors but significantly induced CYP7A1 expression, accompanied by a significant SHP gene suppression. Sulfotransferase 2A1 and BSEP were marginally upregulated, but no other genes were altered by the drugs tested. Protein levels of CYP7A1 were increased with the treatment of CYP7A1 inducers and decreased with obeticholic acid, an farnesoid X receptor ligand. CYP7A1 inducers significantly increased bile acid (BA) production in hepatocytes, indicating the overall regulatory effects of BA metabolism. This study demonstrates that CYP7A1 induction via various mechanisms can pose a risk for DILI, independently or in synergy with BSEP inhibition, and it should be evaluated early in drug discovery. SIGNIFICANCE STATEMENT: Kinase inhibitors, pazopanib and CP-724714, inhibit BSEP and induce CYP7A1 expression independent of small heterodimer partner (SHP) expression, leading to increased bile acid (BA) production and demonstrating clinically elevated drug-induced liver toxicity. MEK1/2 inhibitors that show BSEP-independent drug-induced liver injury (DILI) induced the CYP7A1 gene accompanied by SHP suppression. CYP7A1 induction via SHP-dependent or independent mechanisms can pose a risk for DILI, independently or in synergy with BSEP inhibition. Monitoring BA production in hepatocytes can reliably detect the total effects of BA-related gene regulation for de-risking.

Interaction Between Tacrolimus and Proton Pump Inhibitor in a Kidney Transplant Recipient.

We aimed to present a drug monitoring profile of tacrolimus and proton pump inhibitor coadministration in a 23-year-old male patient with a history of high blood pressure who underwent kidney transplant. The patient's serum trough levels of tacrolimus were in the therapeutic range until omeprazole 20 mg daily was prescribed. Tacrolimus trough serum level increased to 29.5 ng/mL under the same daily dose and to 13.9 ng/mL after tacrolimus daily dose was decreased to 6 mg/day. This increase in tacrolimus serum level was behind a renal function alteration. After withdrawal of omeprazole, tacrolimus trough serum level returned to the therapeutic range. Because interactions between tacrolimus and omeprazole could result in toxicities, careful monitoring of tacrolimus serum levels should be considered to adjust the dosage.

Anti H. pylori, anti-secretory and gastroprotective effects of Thymus vulgaris on ethanol-induced gastric ulcer in Sprague Dawley rats.

The objectives of the present study were to evaluate the acute toxicity, gastroprotective, therapeutic, anti-inflammatory and anti H. pylori activities of T. vulgaris total plant extract against ethanol-induced gastric ulcers in Sprague Dawley rats. Animals were divided into five groups i.e G-1 (Normal Control), Group 2 (ulcer control) were administered orally with 0.5% Carboxymethylcellulose (CMC), Group 3 (omeprazole treated) was administered orally with 20 mg/kg of omeprazole and Groups 4 and 5 (Low dose and High dose of the extract) were administered orally with 250, and 500 mg/ kg of Thymus vulgaris extract, respectively. After 1 hour, the normal group was orally administered with 0.5% CMC (5 ml/kg), whereas absolute alcohol (5ml/ kg) was orally administered to the ulcer control group, omeprazole group, and experimental groups. Stomachs were examined macroscopically and microscopically. Grossly, rats pre-treated with T. vulgaris demonstrated significantly decreased ulcer area and an increase in mucus secretion and pH of gastric content compared with the ulcer control group. Microscopy of gastric mucosa in the ulcer control group showed severe damage to gastric mucosa with edema and leukocytes infiltration of the submucosal layer. However, rats pretreated with omeprazole or Thyme vulgaris exhibited a mild to moderate disruption of the surface epithelium and lower level of edema and leukocyte infiltration of the submucosal layer. The T. vulgaris extract caused up-regulation of Hsp70 protein, down-regulation of Bax protein, and intense periodic acid Schiff uptake of the glandular portion of the stomach. Gastric mucosal homogenate of rats pre-treated with T. vulgaris exhibited significantly increased superoxide dismutase (SOD) and catalase (CAT) activities while malondialdehyde (MDA) level was significantly decreased. Based on the results showed in this study, Thymus vulgaris extract can be proposed as the safe medicinal plants for use and it has considerable gastroprotective potential via stomach epithelium protection against gastric ulcers and stomach lesions.

Effects of treatment with clopidogrel with or without proton pump inhibitor omeprazole on the risk of ischemic stroke: a nationwide cohort study.

Most proton pump inhibitors (PPIs) inhibit the bioactivation of clopidogrel to its active metabolite. There is controversy concerning whether PPIs alter the effectiveness of clopidogrel in reducing the risk of ischemic stroke (IS). We therefore aimed to examine the risk of IS associated with concomitant use of clopidogrel and omeprazole, a PPI commonly used in clinical settings. We conducted a retrospective cohort study using the National Health Insurance Research Database of Taiwan dated from 2000 to 2013. The study cohorts comprised 407 patients diagnosed with acute coronary syndrome (ACS) and with concomitant use of clopidogrel and omeprazole (the exposed cohort), 814 ACS patients with single use of clopidogrel (the comparison cohort), and 230 ACS patients with concurrent use of clopidogrel and pantoprazole (the reference cohort). The primary outcome was incident IS. The hazard ratios (HRs) and 95% confidence intervals (CIs) derived from the time-dependent Cox regression model were used to assess the association between concomitant use of clopidogrel and omeprazole and the risk of IS. The incidence rate of IS was significantly higher in the exposed cohort (81.67 per 1000 person-years) than in the comparison cohort (57.45 per 1000 person-years), resulting in an adjusted HR of 1.39 (95% CI 1.03-1.74). By contrast, there was no significant difference in the risk of IS between the exposed and reference cohorts (adjusted HR 1.11; 95% CI 0.81-1.52). The present study revealed that patients taking both clopidogrel and omeprazole was associated with an increased risk of IS.

Safety of Intravenous Pantoprazole Sodium in Pediatric Patients Aged 1 Month to < 1 Year: A Real-World Retrospective Cohort Study.

OBJECTIVE: To estimate the incidence rates (IR) of prespecified outcomes of interest in pediatric patients (1 month to < 1 year) treated with intravenous (IV) pantoprazole using Optum's longitudinal electronic health records database (Optum Market Clarity) from the United States (US). METHODS: This real-world, non-interventional, retrospective cohort study was conducted from 01 January 2007 to 31 December 2020 in patients who received IV pantoprazole. Premature patients and those weighing < 2.36 kg were excluded. Patients were categorized based on diagnosis of gastroesophageal reflux disease (GERD) and erosive esophagitis (EE) into: Subgroup 1 (GERD and EE), Subgroup 2 (GERD and no EE), and Subgroup 3 (absence of GERD and EE). Overall IRs (per 1000 person-years [PY]) and 95% confidence intervals (CI) of outcomes were estimated (overall and subgroups) and stratified by duration of IV pantoprazole treatment (< 4 days versus ≥ 4 days). RESULTS: Of 1879 eligible patients, none were identified in Subgroup 1; 851 (45.3%) and 1028 (54.7%) patients were identified in Subgroups 2 and 3, respectively. IRs of outcomes of interest ranged from 0.0 to 742.8 per 1000 PY. IRs were highest for vomiting (742.80), diarrhea (377.77), abdominal distension (214.31), hyponatremia (204.99), and hypokalemia (203.49). IRs were comparable between Subgroups 2 and 3. For most outcomes, IRs were higher among patients treated with IV pantoprazole for ≥ 4 days versus those treated for < 4 days. CONCLUSION: These results are consistent with the known safety profile of pantoprazole and emphasize the utility of using real-world data from pediatric populations for assessment of safety outcomes.

A pharmacovigilance study of association between proton-pump inhibitors and rhabdomyolysis event based on FAERS database.

BACKGROUND AND AIM: The association between proton-pump inhibitors (PPIs) and rhabdomyolysis were unclear. The aim of this study was to explore and systematically analyze the potential link between five PPIs and the rhabdomyolysis events using the FDA Adverse Event Reporting System (FAERS) database. METHODS: Suspected rhabdomyolysis events associated with PPIs were identified by data mining with the reporting odds ratio (ROR), proportional reporting ratio (PRR), the information component (IC), and Empirical Bayes Geometric Mean (EBGM). Demographic information, drug administration, and outcomes of PPI-induced rhabdomyolysis events were also analyzed. RESULTS: There were 3311 reports associated with PPI-induced rhabdomyolysis that were identified. After removing duplicates, 1899 cases were determined to contain complete patient demographic data. The average age was 65 ± 18 year and 57% were male. Omeprazole and pantoprazole had the same largest percentage of reports. Lansoprazole had the highest ROR index of 12.67, followed by esomeprazole (11.18), omeprazole (10.27), rabeprazole (10.06), and pantoprazole (9.24). PRR, IC, and EBGM showed similar patterns. This suggested that lansoprazole exhibited the strongest correlation with rhabdomyolysis. In rhabdomyolysis events, PPIs were mainly "concomitant" (>60%), and only a few cases were "primary suspects" (<15%). Rabeprazole showed the lowest death rate while lansoprazole showed the highest. CONCLUSIONS: The study suggested that significant rhabdomyolysis signals were associated with PPIs. Further research should be performed in drug safety evaluation for a more comprehensive association.

Does proton pump inhibitors use increase risk of digestive tumors?: A 2-sample Mendelian randomization study.

The objective of this study was to explore the causal relationship between the use of proton pump inhibitors (PPIs) and 16 types of digestive system tumors. We utilized a 2-sample Mendelian randomization (MR) approach to investigate this relationship. We obtained exposure and outcome data from the UK Biobank and the Finland Biobank, respectively. The genetic data used in the analysis were derived from genome-wide association studies (GWAS) studies conducted on European populations. We screened single nucleotide polymorphisms significantly associated with the use of omeprazole, a commonly used PPIs, as instrumental variables. We then performed MR analyses using the inverse variance weighting (IVW) method, MR-Egger regression, and the weighted median method to evaluate the causal effect of omeprazole use on the 16 types of digestive system tumors. Our MR analysis revealed a significant causal relationship between the use of omeprazole and pancreatic malignancies, but not with any other types of digestive system tumors. The IVW analysis showed an odds ratio of 4.33E-05 (95%CI: [4.87E-09, 0.38], P = .03) and the MR-Egger analysis showed an odds ratio of 5.81E-11 (95%CI: [2.82E-20, 0.12], P = .04). We found no significant heterogeneity or pleiotropy, and sensitivity analysis confirmed the robustness of our results. Furthermore, statistical power calculations suggested that our findings were reliable. Conclusion The use of PPIs is a protective factor for pancreatic malignancies, but no causal relationship has been found with other digestive system tumors.

Unexpected cause of Kounis syndrome: hypersensitivity reaction to omeprazole.

Kounis syndrome is a rare type of acute coronary syndrome (ACS) that occurs as a result of an allergic or anaphylactic reaction. Kounis syndrome can be induced by various medications including antibiotics, proton pump inhibitors, antihypertensive medications, corticosteroids, and antineoplastic medications. Additionally, cases of Kounis syndrome associated with lansoprazole and pantoprazole have been previously reported in the literature. In this report, we present a case of Kounis syndrome associated with omeprazole use, and discuss the need for a high index of suspicion as it is often underrecognised.

Is the Addition of Sublingual Melatonin to Omeprazole Superior to Omeprazole Alone in the Management of Gastroesophageal Reflux Disease Symptoms: A Clinical Trial.

BACKGROUND/AIMS: Proton pump inhibitors are frequently used to treat gastroesophageal reflux disease, but their effect is restricted. The present study aimed to investigate whether the addition of sublingual melatonin to omeprazole was effective in the treatment of gastro gastroesophageal reflux disease symptoms. MATERIALS AND METHODS: This was a randomized double-blind clinical trial. A total of 78 patients with gastro gastroesophageal reflux disease were randomly allocated to either omeprazole 20 mg/d plus sublingual melatonin (3 mg/d) or omeprazole 20 mg/d plus placebo for 4 weeks. The selected patients had histories of heartburn and regurgitation and a score ≤32 on the Frequency Scale for the Symptoms of gastroesophageal reflux disease (FSSG). The outcome measures for the assessment of treatment efficacy were heartburn, epigastric pain and the Frequency Scale for the Symptoms of gastroesophageal reflux disease score. Safety and quality of life were evaluated in the patients as the secondary outcomes too. RESULTS: Seventy-two out of 78 eligible patients completed this trial (35 in the melatonin group and 37 in the placebo group). Heartburn, epigastric pain, and Frequency Scale for the Symptoms of gastroesophageal reflux disease score declined significantly in the melatonin group compared to the placebo group (P = .04, P = .03, and P = .0001, respectively). Moreover, the quality of life score was significantly higher in the melatonin group compared with the placebo group (P = .0001). Adverse events were similarly observed in the 2 groups (P = .55), and there were no serious adverse events. CONCLUSION: The combination of sublingual melatonin (3 mg/day) with omeprazole (20 mg/day) may be more effective than omeprazole (20 mg/day) alone in the treatment of gastroesophageal reflux disease.

Gastric development of pancreatic acinar cell metaplasia after Vonoprazan therapy in rats.

BACKGROUND: Vonoprazan is a new acid-suppressing drug that received FDA approval in 2022. It reversibly inhibits gastric acid secretion by competing with the potassium ions on the luminal surface of the parietal cells (potassium-competitive acid blockers or P-CABs). Vonoprazan has been on the market for a short time and there are many clinical trials to support its clinical application. However, medical experience and comprehensive clinical data is still limited, especially on how and if, gastric histology is altered due to therapy. METHODS: A 12-week experiment trial with 30 Wistar rats was to assess the presence of gastrointestinal morphologic abnormalities upon administration of omeprazole and vonoprazan. At six weeks of age, rats were randomly assigned to one of 5 groups: (1) saline as negative control group, (2) oral omeprazole (40 mg/kg), as positive control group, (3) oral omeprazole (40 mg/kg) for 4 weeks, proceeded by 8 weeks off omeprazole, (4) oral vonoprazan (4 mg/kg), as positive control group, and (5) oral vonoprazan (4 mg/kg) for 4 weeks, proceeded by 8 weeks off vonoprazan. RESULTS: We identified non-inflammatory alterations characterized by parietal (oxyntic) cell loss and chief (zymogen) cell hyperplasia and replacement by pancreatic acinar cell metaplasia (PACM). No significant abnormalities were identified in any other tissues in the hepatobiliary and gastrointestinal tracts. CONCLUSION: PACM has been reported in gastric mucosa, at the esophagogastric junction, at the distal esophagus, and in Barrett esophagus. However, the pathogenesis of this entity is still unclear. Whereas some authors have suggested that PACM is an acquired process others have raised the possibility of PACM being congenital in nature. Our results suggest that the duration of vonoprazan administration at a dose of 4 mg/kg plays an important role in the development of PACM.

Safety analysis of co-administering tacrolimus and omeprazole in renal transplant recipients - A review.

Tacrolimus is a calcineurin inhibitor used to prevent rejection in allogenic solid organ transplant recipients, which is metabolized in the liver with cytochrome P450 isoforms 3A4 and 3A5 (CYP3A4, CYP3A5). In turn, proton pump inhibitors (PPIs), such as Omeprazole - a substrate and inhibitor of CYP2C19 and CYP3A4 enzymes - are administered to kidney transplant patients in order to prevent duodenal and gastric ulcer disease, associated with the glucocorticoid treatment. Simultaneous administration of both drugs in renal patients has the potential to trigger drug interactions. In fact, there are several mechanisms which may impact the pharmacokinetics of tacrolimus. Inhibition of the CYP2C19 isoform may suppress the metabolism of omeprazole, subsequently altering its metabolic pathway to be metabolized by the CYP3A4 enzyme in order to maintain adequate biotransformation. Therefore, the competition for CYP3A4 may affect the metabolism of tacrolimus and result in its increased plasma concentrations, as well as in adverse reactions. Another mechanism has been related to the genetic polymorphism of the CYP2C19 isoform. Since all these interactions may lead to dysfunctions of the transplanted kidney, it seems significant to eliminate their consequences, for instance via the administration of drugs which are neither substrates, nor inhibitors of the CYP3A4 enzyme. Finally, the nephrotoxic effect of omeprazole should also be accounted for. Bearing in mind the aforementioned observations, the aim of the presented paper was to review the available studies addressing the effect of omeprazole on the pharmacokinetics of tacrolimus.

CYP2C19 loss-of-function alleles and use of omeprazole or esomeprazole increase the risk of cardiovascular outcomes in patients using clopidogrel.

Our aim was to investigate in a real-life prospective patient cohort how CYP2C19 loss-of-function (LOF) variants and CYP2C19 inhibitor omeprazole or esomeprazole influence the incidence of cardiovascular events in patients using clopidogrel. Data based simultaneously on these factors are conflicting and sparse. A cohort of prospective patients (n = 1972) with acute coronary syndrome (n = 1302) or symptomatic chronic coronary disease (n = 656) was followed for 365 days after hospitalization with information on purchased prescription drugs, hospital discharge, death, and genotype for CYP2C19*2, CYP2C19*3, and CYP2C19*8 LOF variants. The primary study outcome measurement was cardiovascular death or recurring myocardial infarction or stroke. Altogether, 608 patients (30.8%) carried CYP2C19 LOF alleles. During the 365-day follow-up 252 patients (12.8%) had an ischemic vascular event. Cardiovascular events were significantly more frequent in carriers of CYP2C19 LOF alleles (14.8%, 95% confidence interval [CI], 11.7-17.8) than in non-carriers (10.8%, 95% CI, 9.0-12.6, p = 0.0159). Omeprazole or esomeprazole use was similar among LOF allele carriers (n = 131, 21.5%) and non-carriers (n = 250, 18.3%, p = 0.185). Cardiovascular events were significantly more common in a composite group consisting of all CYP2C19 LOF carriers regardless of proton pump inhibitor use status and non-carriers using omeprazole or esomeprazole than in non-carriers not using omeprazole or esomeprazole (14.8%, 95% CI, 12.2-17.3 vs. 9.9%, 95% CI, 8.0-11.9, p = 0.00173). We observed significantly more cardiovascular events in carriers of CYP2C19 LOF variants and in non-carriers using omeprazole or esomeprazole. For optimal patient care, both genetics and concomitant medication should be considered.

Structural characterization of the optical isomers esomeprazole and omeprazole using the JADER and FAERS databases.

BACKGROUND: It is unclear whether the s (-) form of esomeprazole (EPZ) has an improved safety profile when compared with its racemic form omeprazole (OPZ). We assessed the potential complications of these optical isomers when combined with cilostazol, clopidogrel, and prasugrel, which are frequently used concomitant medications. METHODS: Using two adverse event spontaneous reporting databases, Japanese Adverse Drug Event Report (JADER) and FDA Adverse Event Reporting System (FAERS), adverse event names for hemorrhage, venous/arterial embolization, and thrombus were obtained from the Medical Dictionary for Regulatory Activities. Reported odds ratios were calculated using a 2 × 2 contingency table, and a signal was considered present if the lower limit of the 95% confidence interval was >1. RESULTS: In combination with cilostazol, a hemorrhagic signal for OPZ in JADER and arterial emboli and thrombus signals for EPZ were detected in both databases. In combination with clopidogrel, OPZ showed arterial emboli and thrombus signals in JADER and venous/arterial emboli and thrombus signals in FAERS, while EPZ displayed arterial emboli and thrombus signals in FAERS. In contrast, when in combination with prasugrel, there were no adverse event signals in either database. CONCLUSION: This study has confirmed using big data, that EPZ, the optical isomer and racemic form of omeprazole, has the beneficial characteristics of being less sensitive to CYP, as was intended by its design.

Different effects of chronic omeprazole use on osteoporotic fractures rate in the elderly.

AIMS: To investigate the potential association of chronic use of omeprazole with the occurrence of osteoporotic fractures (OF) in community-dwelling elderly subjects. METHODS: The cohort consisted of community-dwelling residents aged >65 years registered with a large health maintenance organization in Israel between January 2002 and December 2016. Data were retrospectively collected from the electronic medical files on demographics, parameters known to be associated with OF, diagnoses of osteoporotic hip, wrist, and vertebral fractures, and chronic use of omeprazole (>11 prescriptions/year). Time to OF/death/end of study was calculated from the beginning of the study (2002). The risk of fractures in the chronic users of omeprazole was analyzed by multivariate Cox proportional hazard regression model. RESULTS: In total, 46 805 subjects were included (41% men), mean age 83.4±6.4 years, of whom 10 272 (21.9%) were chronic users of omeprazole. During 14 years of follow-up, OF were diagnosed in 414 (4.0%) omeprazole users and 1007 (2.8%) omeprazole nonusers (p < 0.001). In a Cox regression model adjusted for age and gender only, chronic use of omeprazole was associated with a 16% excess of OF. However, when parameters known to be associated with OF were entered into the multivariate Cox regression model, chronic use of omeprazole was not found to be an independent risk factor for OF, either overall (adjusted hazard ratio = 0.965, 95% confidence interval 0.86-1.08, P = .55) or specifically, in the ≥85 years age group (adjusted hazard ration = 0.780, 95% confidence interval 0.635-0.958, P < .05) in which an inverse correlation between omeprazole use and OF, was demonstrated. CONCLUSIONS: Chronic use of omeprazole was not associated with the occurrence of OF in elders.

Gastric cancer risk in the elderly is associated with omeprazole use and inversely associated with aspirin use.

BACKGROUND: The association between long-term omeprazole use and gastric cancer (GC) risk is controversial. The aim of this study was to investigate the incidence of GC in elderly community-dwelling omeprazole chronic users with/without aspirin compared to non-users. METHODS: The registry of a large health management organization was searched for all community-dwelling members aged ≥65 years from January 2002 to December 2016. Data on demographics, background parameters, and chronic omeprazole and aspirin use (>11 prescriptions/year) were retrieved. Those diagnosed with new-onset GC during the study period (from January 2003) were identified. RESULTS: Of 51 405 subjects who met the inclusion criteria, 197 were diagnosed with GC during a mean follow-up period of 8.74 ±â€…4.16 years. This group accounted for 0.7% of PPI chronic users (72/11 008) and 0.3% (125/40 397) of nonusers (P < 0.001). GC risk was directly associated with omeprazole chronic use [hazard ratio (HR) 2.03, 95% confidence interval (CI): 1.51-2.73, P < 0.001] and inversely associated with aspirin chronic use (HR 0.55, 95% CI: 0.40-0.75, P < 0.001). Each year of omeprazole use increased GC risk by 9%, and each year of aspirin use decreased GC risk by 10% among omeprazole chronic users. The lowest rate of GC was found in omeprazole nonusers/ aspirin chronic users, and the highest, in omeprazole chronic users/aspirin nonusers. CONCLUSION: Higher GC rate was associated with omeprazole chronic use and inversely associated with aspirin chronic use relative to omeprazole nonuse in community-dwelling elderly.

PPIs and gastric cancer: any causal relationship?

Hydrochloric acid is crucial in gastric physiology. In 1978 cimetidine, the first H2 antagonist of histamine receptors on the gastric parietal cell was introduced into therapy, inducing acid. Lasting the years, several studies focused on the potential relationship between inducing hypo-achlorhydria and risk of developing gastric cancer. In 1988 omeprazole, the first proton pump inhibitor, entered therapy. In 1996, Kuipers underlined the danger of progression of chronic atrophic gastritis in subjects taking PPIs. In 2018, one paper from Korea and an another on from Sweden suggested a possible relationship between long-term PPI therapy and the development of gastric cancer. Over the years, several articles, meta-analyzes and population based  focused on relationship between long-term of PPI use and the onset of gastric cancer, with conflicting results. As reported, the presence of bias in the collection of cases, in particular concerning the evaluation of the H.p. status and presence of atrophic gastritis and intestinal metaplasia in subjects treated with PPI, can lead to noticeable errors in the results and conclusions, as demonstrated in the literature by exhaustive methodological studies of pharmacoepidemiology. A possible bias in the collection of case histories is due to the fact that PPIs are often administered to dyspeptic patients, among which there are patients already carriers of gastric neoplasia: the so-called inverse causality.  Literature data, amended by methodological bias (sampling errors, lack of comparative assessment of Hp status and atrophic gastritis) NOT support a causal relationship between long-term PPIs therapy and the onset of gastric cancer.

Effect of Firocoxib and Flunixin Meglumine on Large Colon Mural Thickness of Healthy Horses.

Nonsteroidal anti-inflammatory drug (NSAID) administration carries risks of gastrointestinal toxicity. Selective COX-2 inhibitors ("coxibs") were designed to reduce risks of adverse effects but are still associated with gastrointestinal complications in humans. The effect of coxibs on colonic inflammation and integrity in horses is unknown. The study objective was to compare the effects of the coxib firocoxib and the nonselective NSAID flunixin meglumine on ultrasonographic indicators of colonic inflammation in healthy horses. Twelve healthy adult horses were administered flunixin meglumine (1.1 mg/kg IV q12h) and omeprazole (1 mg/kg PO q24h) for 5 days, allowed a 6-month washout period, then administered firocoxib (0.3 mg/kg PO once, then 0.1 mg/kg PO q24h for 4 days) and omeprazole. Transabdominal ultrasonographic examination and serum chemistry profiles were performed at the beginning and end of each treatment week. Colon wall thickness increased over time when horses received firocoxib (median post treatment 5.8 mm, interquartile range 2.8 mm; P < .001), but not flunixin (median 3 mm, interquartile range 1.2 mm; P = .7) and was significantly greater following firocoxib compared to flunixin (P = .003). Subjectively, colonic edema was noted more frequently following treatment with firocoxib (11/12 horses), compared to flunixin (1/12 horses). There were no clinically significant alterations in hematologic parameters after administration of either drug. The increase in colon wall thickness following treatment with the COX-2 selective NSAID firocoxib may suggest a risk of subclinical colitis in healthy horses. Monitoring colonic health when NSAIDs are used in a clinical setting is warranted.