Histamine H2-receptor antagonism improves conduit artery endothelial function and reduces plasma aldosterone level without lowering arterial blood pressure in angiotensin II-hypertensive mice.

Aldosterone through the mineralocorticoid receptor MR has detrimental effects on cardiovascular disease. It reduces the bioavailability of nitric oxide and impairs endothelium-dependent vasodilatation. In resistance arteries, aldosterone impairs the sensitivity of vascular smooth muscle cells to nitric oxide by promoting the local secretion of histamine which activates H2 receptors. The present experiments tested in vivo and ex vivo the hypothesis that systemic H2-receptor antagonism reduces arterial blood pressure and improves vasodilatation in angiotensin II-induced chronic hypertension. Hypertension was induced by intravenous infusion of angiotensin II (60 ng kg-1 min-1) in conscious, unrestrained mice infused concomitantly with the H2-receptor antagonist ranitidine (27.8 µg kg-1 min-1) or vehicle for 24 days. Heart rate and arterial blood pressure were recorded by indwelling arterial catheter. Resistance (mesenteric) and conductance (aortae) arteries were harvested for perfusion myography and isometric tension recordings by wire myography, respectively. Plasma was analyzed for aldosterone concentration. ANGII infusion resulted in elevated arterial blood pressure and while in vivo treatment with ranitidine reduced plasma aldosterone concentration, it did not reduce blood pressure. Ranitidine improved ex vivo endothelial function (acetylcholine 10-9 to 10-6 mol L-1) in mesenteric resistance arteries. This was abolished by ex vivo treatment with aldosterone (10-9 mol L-1, 1 h). In aortic segments, in vivo ranitidine treatment impaired relaxation. Activation of histamine H2 receptors promotes aldosterone secretion, does not affect arterial blood pressure, and protects endothelial function in conduit arteries but promotes endothelial dysfunction in resistance arteries during angiotensin II-mediated hypertension. Aldosterone contributes little to angiotensin II-induced hypertension in mice.

Exclusion of Ranitidine From Premedication Regimens During Paclitaxel Treatment.

This cohort study conducted in the Netherlands uses electronic medical records to assess incidence of hypersensitivity reactions with and without H2-receptor antagonist premedication before paclitaxel administration.

Drug Utilisation Patterns of Alternatives to Ranitidine-Containing Medicines in Patients Treated with Ranitidine: A Network Analysis of Data from Six European National Databases.

INTRODUCTION: Ranitidine, a histamine H2-receptor antagonist (H2RA), is indicated in the management of gastric acid-related disorders. In 2020, the European Medicines Agency (EMA) recommended suspension of all ranitidine-containing medicines in the European Union (EU) due to the presence of N-nitrosodimethylamine (NDMA) impurities, which were considered to be carcinogenic. The aim of this study was to investigate the impact of regulatory intervention on use patterns of ranitidine-containing medicines and their therapeutic alternatives. OBJECTIVES: The aim was to study drug utilisation patterns of ranitidine and report discernible trends in treatment discontinuation and switching to alternative medications. METHODS: This retrospective, population-based cohort study was conducted using primary care records from six European countries between 2017 and 2023. To explore drug utilisation patterns, we calculated (1) incident use of ranitidine, other H2RAs, and other alternative drugs for the treatment of gastric ulcer and/or gastric bleeding; (2) ranitidine discontinuation; and (3) switching from ranitidine to alternative drugs (H2RAs, proton-pump inhibitors [PPIs], and other medicinal products for acid-related disorders). RESULTS: During the study period, 385,273 new ranitidine users were observed, with most users being female and aged 18-74 years. Ranitidine was the most commonly prescribed H2RA in the pre-referral period (September 2017-August 2019), with incidence rates between 0.8 and 9.0/1000 person years (PY). A steep decline to 0.3-3.8/1000 PY was observed in the referral period (September 2019-March 2020), eventually dropping to 0.0-0.4/1000 PY in the post-referral period (April 2020-March 2022). Switching from ranitidine to alternative drugs increased in the post-referral period, with the majority of patients switching to PPIs. Discontinuation of ranitidine use ranged from 270 to 380/1000 users in 2017 and decreased over time. CONCLUSIONS: Ranitidine was commonly used prior to referral, but it was subsequently discontinued and replaced primarily with PPIs.

Ranitidine Use and Incident Cancer in a Multinational Cohort.

Importance: Ranitidine, the most widely used histamine-2 receptor antagonist (H2RA), was withdrawn because of N-nitrosodimethylamine impurity in 2020. Given the worldwide exposure to this drug, the potential risk of cancer development associated with the intake of known carcinogens is an important epidemiological concern. Objective: To examine the comparative risk of cancer associated with the use of ranitidine vs other H2RAs. Design, Setting, and Participants: This new-user active comparator international network cohort study was conducted using 3 health claims and 9 electronic health record databases from the US, the United Kingdom, Germany, Spain, France, South Korea, and Taiwan. Large-scale propensity score (PS) matching was used to minimize confounding of the observed covariates with negative control outcomes. Empirical calibration was performed to account for unobserved confounding. All databases were mapped to a common data model. Database-specific estimates were combined using random-effects meta-analysis. Participants included individuals aged at least 20 years with no history of cancer who used H2RAs for more than 30 days from January 1986 to December 2020, with a 1-year washout period. Data were analyzed from April to September 2021. Exposure: The main exposure was use of ranitidine vs other H2RAs (famotidine, lafutidine, nizatidine, and roxatidine). Main Outcomes and Measures: The primary outcome was incidence of any cancer, except nonmelanoma skin cancer. Secondary outcomes included all cancer except thyroid cancer, 16 cancer subtypes, and all-cause mortality. Results: Among 1 183 999 individuals in 11 databases, 909 168 individuals (mean age, 56.1 years; 507 316 [55.8%] women) were identified as new users of ranitidine, and 274 831 individuals (mean age, 58.0 years; 145 935 [53.1%] women) were identified as new users of other H2RAs. Crude incidence rates of cancer were 14.30 events per 1000 person-years (PYs) in ranitidine users and 15.03 events per 1000 PYs among other H2RA users. After PS matching, cancer risk was similar in ranitidine compared with other H2RA users (incidence, 15.92 events per 1000 PYs vs 15.65 events per 1000 PYs; calibrated meta-analytic hazard ratio, 1.04; 95% CI, 0.97-1.12). No significant associations were found between ranitidine use and any secondary outcomes after calibration. Conclusions and Relevance: In this cohort study, ranitidine use was not associated with an increased risk of cancer compared with the use of other H2RAs. Further research is needed on the long-term association of ranitidine with cancer development.

Is ranitidine necessary as premedication for regimens containing paclitaxel? A non-inferiority study.

BACKGROUND: Histamine type-2-receptor antagonist drugs (H2-antagonists) have been used as standard treatment to prevent hypersensitivity reactions (HRs) in paclitaxel-containing regimens, however, their use has been strongly questioned. Ranitidine has been the most widely used H2-antagonist. Therefore, especially after its withdrawal from the market, the objective of this study is to determine the impact of its elimination from premedication on HR incidence. METHODS: A cohort, multicenter, observational, prospective, and non-inferiority study, including paclitaxel-naïve cancer patients, designed to determine the incidence of HRs of any grade associated with paclitaxel administration and analyze non-inferiority against the incidence estimated in the literature (20%), with 5% as the maximum difference (Δ). Patients with a solid neoplasm of any type/stage, who initiated treatment with paclitaxel without H2-antagonists in the premedication regimen were enrolled. RESULTS: A total of 441 patients were included, of whom 50 presented 54 HRs of any grade. The cumulative incidence was 11.3% (95%CI 8.5-14.7), thus fulfilling the hypothesis of non-inferiority. Of the overall HRs detected, 15 were grade ≥ 3 with a cumulative incidence of 3.4% (95%CI 1.9-5.5). CONCLUSIONS: This study demonstrates that the elimination of ranitidine from paclitaxel premedication schedules is non-inferior in the development of HRs of any grade compared to the administration of H2-antagonists.

Phytochemical Estimation and Therapeutic Amelioration of Aesculus hippocastanum L. Seeds Ethanolic Extract in Gastric Ulcer in Rats Possibly by Inhibiting Prostaglandin Synthesis.

OBJECTIVE: To quantify phytochemicals using liquid chromatography and mass spectroscopy (LCMS) analysis and explore the therapeutic effect of Aesculus hippocastanum L. (AH) seeds ethanolic extract against gastric ulcers in rats. METHODS: Preliminary phytochemical testing and LCMS analysis were performed according to standard methods. For treatment, the animals were divided into 7 groups including normal control, ulcer control, self-healing, AH seeds low and high doses, ranitidine and per se groups. Rats were orally administered with 10 mg/kg of indomethacin, excluding the normal control group (which received 1% carboxy methyl cellulose) and the per se group (received 200 mg/kg AH seeds extract). The test group rats were then given 2 doses of AH seeds extract (100 and 200 mg/kg, respectively), while the standard group was given ranitidine (50 mg/kg). On the 11th day, rats in all groups were sacrificed, and their stomach was isolated to calculate the ulcer index, and other parameters such as blood prostaglandin (PGE2), tissue superoxide dismutase (SOD), catalase (CAT), malonyldialdehyde (MDA), and glutathione (GSH). All isolated stomach tissues were analyzed for histopathological findings. RESULTS: The phytochemical examination shows that the AH seeds contain alkaloids, flavonoids, saponins, phenolic components, and glycosides. LCMS analysis confirms the presence of quercetin and rutin. The AH seeds extract showed significant improvement in gastric mucosa conditions after indomethacin-induced gastric lesions (P<0.01). Further marked improvement in blood PGE2 and antioxidant enzymes, SOD, CAT, MDA and GSH, were observed compared with self-healing and untreated ulcer-induced groups (P<0.01). Histopathology results confirmed that AH seeds extract improved the mucosal layer and gastric epithelial membrane in treated groups compared to untreated ulcer-induced groups. CONCLUSIONS: LCMS report confirms the presence of quercetin and rutin in AH seeds ethanolic extract. The therapeutic effect of AH seeds extract against indomethacin-induced ulcer in rat model indicated the regenerated membrane integrity, with improved cellular functions and mucus thickness. Further, improved antioxidant enzyme level would help to reduce PGE2 biosynthesis.

Prescription changes in patients with gastrointestinal disorders after withdrawal of ranitidine: a nationwide population-based cohort study.

OBJECTIVE: Ranitidine products contain unacceptable levels of N-nitrosodimethylamine. This study aimed to investigate changes in the treatment regimen and their influencing factors after the ranitidine recall. METHODS: This retrospective study used data from nationwide Korean claims from 2019. Patients with gastrointestinal disorders treated with ranitidine for at least a month on 25 September 2019, were selected for this study. Other histamine-2 receptor antagonists (H2RAs), proton pump inhibitors (PPIs), potassium-competitive acid blockers (PCABs), and prostaglandin E1 analogs were administered as alternatives to ranitidine. Kaplan-Meier survival and Cox proportional hazards regression analyses were performed to gauge the time until switching to alternative drugs and assess the influencing factors. RESULTS: In total, 7502 patients were included in this study, among which 5164 (68.8%) switched from ranitidine to an alternative drug. The most prescribed alternative drugs were H2RAs, followed by PPIs, PCABs, and prostaglandin E1 analogs. Increasing age; Medical Aid insurance (MedAid); and a history of hypertension, diabetes mellitus, asthma, and osteoarthritis were associated with a higher probability of switching treatments. Patients with concomitant gastroesophageal reflux disease and peptic ulcers were more likely to switch to alternative drugs than patients with gastritis. CONCLUSIONS: Approximately two-thirds of patients with gastrointestinal disorders switched from ranitidine to alternative drugs within 3 months after ranitidine withdrawal. The Cox regression analysis showed that age (>55 years); insurance type (MedAid); comorbidities, such as hypertension, diabetes mellitus, asthma, and osteoarthritis, and gastrointestinal disorder severity influenced the switch from ranitidine to alternative drugs.

Association between ranitidine use with potential NDMA impurities and risk of cancer in Korea.

N-Nitrosodimethylamine (NDMA) detected above the acceptable level in ranitidine products has been a great global concern. To examine the risk of cancer among people treated with ranitidine, we conducted a cohort study using the National Health Insurance Service-National Sample Cohort data (2002-2015) of South Korea. Patients were aged 40 or above as of January 2004 and began receiving ranitidine or other histamine-2 receptor antagonist (H2RA), active comparator, without a history of H2RAs prescription during the prior 2-years. The lag time was designated up to 6 years. The outcomes were an overall incident cancer risk and the risk of major single cancers during the follow-up. The association between ranitidine use and cancer risk was examined by Cox regression model. After exclusion and propensity score matching, 25,360 patients were available for analysis. The use of ranitidine was not associated with the overall cancer risk and major individual cancers [overall cancer: incidence rate per 1000 person-years, 2.9 vs 3.0 among the ranitidine users and other H2RAs users, respectively; adjusted hazard ratio (HR) and 95% confidence interval (95% CI) for all cancers, 0.98 (0.81-1.20)]. The higher cumulative exposure to ranitidine did not increase the cancer risk. Given the insufficient follow-up period, these findings should be interpreted carefully.

Ranitidine and the incidence of hypersensitivity reactions to paclitaxel: A retrospective cohort study.

Paclitaxel is a commonly used chemotherapeutic agent. To minimize the risk of hypersensitivity reactions (HSRs), which occur in approximately 16-42% of patients, premedication with dexamethasone, clemastine, and ranitidine was standard of care. As of October 2019, ranitidine is no longer available. We compared the risk of HSRs to paclitaxel with and without premedication with ranitidine, hypothesizing that the incidence of HSRs to paclitaxel will be similar. In this retrospective cohort study, all first-time paclitaxel users in the Groene Hart Hospital were included from January 2019 to August 2020. The primary outcome was the incidence of HSRs, using a Student's t-test. One-hundred and eight patients who were first-time users of paclitaxel in the Groene Hart Hospital met the inclusion criteria. Most patients were treated for breast or ovarian cancer, followed by lung cancer. Analysis of all 836 paclitaxel administrations was performed. Following 349 administrations with ranitidine as premedication, eight HSRs occurred (2.3%), while following 487 administrations without ranitidine, 12 HSRs occurred (2.5%), p-value of 0.87. An additional analysis on the occurrence of HSRs per patient was performed: 45 patients received premedication in the form of ranitidine, of which eight patients (17.8%) had a HSR. Sixty-three patients did not receive premedication in the form of ranitidine, of whom 10 (15.8%) had a HSR, p-value of .80. In conclusion, we found no difference in the incidence of HSRs during paclitaxel infusions between patients who received ranitidine as premedication versus those who did not.

Ranitidine Use and Gastric Cancer Among Persons with Helicobacter pylori.

BACKGROUND: The Food and Drug Administration requested withdrawal of ranitidine formulations, due to a potentially carcinogenic contaminant, N-nitrosodimethylamine. AIMS: We evaluate whether ranitidine use is associated with gastric cancer. METHODS: This is a retrospective multicenter, nationwide cohort study within the Veterans Health Administration, among patients with Helicobacter pylori (HP) prescribed long-term acid suppression with either: (1) ranitidine, (2) other histamine type 2 receptor blocker (H2RB), or (3) proton pump inhibitor (PPI)) between May 1, 1998, and December 31, 2018. Covariates included race, ethnicity, smoking, age, HP treatment, HP eradication. Primary outcome was non-proximal gastric adenocarcinomas, using multivariable Cox proportional hazards analysis. RESULTS: We identified 279,505 patients with HP prescribed long-term acid suppression (median 53.4 years; 92.9% male). Compared to ranitidine, non-ranitidine H2RB users were more likely to develop cancer (HR 1.83, 95%CI 1.36-2.48); PPI users had no significant difference in future cancer risk (HR 0.92, 95% CI 0.82-1.04), p < 0.001. Demographics associated with future cancer included increasing age (HR 1.18, 95% CI 1.15-1.20, p < 0.001), Hispanic/Latino ethnicity (HR 1.46, 95% CI 1.21-1.75, p < 0.001), Black race (HR 1.89, 95% CI 1.68-2.14) or Asian race (HR 2.03, 95% CI 1.17-3.52), p < 0.001, and gender (female gender HR 0.64, 95% CI 0.48-0.85, p = 0.02). Smoking was associated with future cancer (HR 1.38, 95% CI 1.23-1.54, p < 0.001). Secondary analysis demonstrated decreased cancer risk in those with confirmed HP eradication (HR 0.24, 95% CI 0.14-0.40). No association between ranitidine and increased gastric cancer was found. CONCLUSION: There is no demonstrable association between ranitidine use and future gastric cancer among individuals with HP on long-term acid suppression.

Ranitidine and Risk of Bladder and Kidney Cancer: A Population-Based Cohort Study.

BACKGROUND: In 2019, ranitidine was withdrawn due to high levels of N-nitrosodimethylamine, a probable human carcinogen. The risk of bladder and kidney cancer in ranitidine users, however, remains unclear. METHODS: In a Danish nationwide cohort study, we included adults (18 years or older) without previous cancer, who between 1996 and 2008 redeemed at least two prescriptions for ranitidine and, as two separate comparison cohorts, patients with at least two prescriptions for other H2-receptor antagonists (H2-blockers), or proton pump inhibitors (PPI). Follow-up for bladder or kidney cancer started at date of the second prescription and continued to date of cancer, death, emigration, or December 31, 2018, whichever occurred first. We used propensity scores for ranitidine use to compute stabilized inverse probability of treatment (sIPT) weights and used Cox regression to compute crude and weighted HRs. RESULTS: We identified 31,393 initiators of ranitidine, 65,384 initiating other H2-blockers, and 509,849 initiating PPI. Compared with other H2-blockers, the crude HR for bladder cancer was 1.33 [95% confidence interval (CI): 1.15-1.55], but sIPT weighting attenuated this to 1.11 (95% CI: 0.95-1.29). Compared with PPI initiators, the weighted HR was 1.24 (95% CI: 1.04-1.48). For kidney cancer, the weighted HR was 0.89 (95% CI: 0.72-1.10) compared with users of H2-blockers and 0.87 (95% CI: 0.67-1.13) compared with users of PPI. CONCLUSIONS: Our findings did not suggest a substantial increase in bladder or kidney cancer occurrence in ranitidine users. IMPACT: These findings are reassuring for previous ranitidine users.

Ranitidine Use and Risk of Upper Gastrointestinal Cancers.

BACKGROUND: The discovery that ranitidine is contaminated with N-nitrosodimethylamine, a suspected human carcinogen, raises the hypothesis of a gastrointestinal carcinogenic effect; however, evidence remains inconclusive. METHODS: We used the nationwide Danish Prescription Registry to identify a cohort of incident ranitidine users and two active comparator cohorts comprising users of other histamine-2 receptor blockers (H2RB) and users of proton pump inhibitors (PPI). All Danish adults with a first prescription of ranitidine, other H2RBs, or PPIs in 1996 through 2008 were followed virtually completely through 2018 for incidence of esophageal, stomach, liver, and pancreatic cancers. We used Cox regression with propensity-score weighting to calculate hazard ratios and 10-year cumulative risk with 95% confidence intervals. RESULTS: We ascertained 276 newly diagnosed esophageal, 342 stomach, 133 hepatocellular, and 517 pancreatic cancers among ranitidine users during follow-up (median 14 years). In comparison with use of other H2RBs or PPIs, we found no consistent evidence of increased HRs or excess 10-year cumulative risk of any upper gastrointestinal cancer following ranitidine use. We observed no association after restriction to subjects with at least 5 or 10 prescriptions or those with 10 prescriptions and at least 10 years of follow-up. CONCLUSIONS: Our large prospective study using high-quality prescription and cancer incidence data, with two active comparator groups, provides no compelling evidence that ranitidine increases the risk of upper gastrointestinal cancers. IMPACT: Our results, which do not support any carcinogenic effect on esophagus, stomach, liver or pancreas, should be reassuring for millions of concerned past users of ranitidine.

No association between chronic use of ranitidine, compared with omeprazole or famotidine, and gastrointestinal malignancies.

BACKGROUND: In 2019, the United States Food and Drug Administration detected above-regulation levels of the human carcinogen N-nitrosodimethylamine (NDMA) in ranitidine, resulting in a complete removal of the medication from the market. NDMA is known to cause gastrointestinal malignancies in animal models. AIM: To determine if patients who were receiving ranitidine have a higher risk of developing cancers of the digestive tract compared to patients taking other anti-reflux medications. METHODS: Using the nationwide database IBM Explorys, patients taking ranitidine were compared to patients on either famotidine or omeprazole. Incidence data of new malignancies of the oesophagus, stomach, liver, pancreas, and colon/rectum were obtained in 1-year intervals for up to 10 years. Two multivariable logistic regression models were used to calculate odds ratios (ORs), one adjusting for common risk factors for each cancer studied, and the other for demographic factors. RESULTS: Patients on ranitidine who were compared to patients on famotidine had ORs of 0.51(95% CI 0.43-0.60), 0.43(95% CI 0.36-0.51), 0.39(95% CI 0.36-0.41), 0.54(95% CI 0.49-0.62), and 0.46(95% CI 0.43-0.49) of developing oesophageal, gastric, hepatocellular, pancreatic, and colorectal cancers, respectively (P < 0.001). Patients on ranitidine compared to omeprazole had ORs of 0.62(95% CI 0.52-0.72), 0.58(95% CI 0.49-0.68), 0.81 (95% CI 0.76-0.86), 0.68(95% CI 0.60-0.76), and 0.66(95% CI 0.62-0.70) of developing oesophageal, gastric, hepatocellular, pancreatic, and colorectal cancers respectively (P < 0.001). CONCLUSIONS: Use of ranitidine was not associated with an increased odds of developing gastrointestinal malignancies compared to omeprazole or famotidine use.

Histamine receptor 2 blockade selectively impacts B and T cells in healthy subjects.

Histamine receptor 2 (H2R) blockade is commonly used in patients with gastric, duodenal ulcers or gastroesophageal reflux disease. Beyond the gastrointestinal tract, H2R is expressed by multiple immune cells, yet little is known about the immunomodulatory effects of such treatment. Clinical reports have associated H2R blockade with leukopenia, neutropenia, and myelosuppression, and has been shown to provide clinical benefit in certain cancer settings. To systematically assess effects of H2R blockade on key immune parameters, a single-center, single-arm clinical study was conducted in 29 healthy subjects. Subjects received daily high dose ranitidine for 6 weeks. Peripheral blood immunophenotyping and mediator analysis were performed at baseline, 3 and 6 weeks into treatment, and 12 weeks after treatment cessation. Ranitidine was well-tolerated, and no drug related adverse events were observed. Ranitidine had no effect on number of neutrophils, basophils or eosinophils. However, ranitidine decreased numbers of B cells and IL-2Rα (CD25) expressing T cells that remained lower even after treatment cessation. Reduced serum levels of IL-2 were also observed and remained low after treatment. These observations highlight a previously unrecognised immunomodulatory sustained impact of H2R blockade. Therefore, the immune impacts of H2R blockade may require greater consideration in the context of vaccination and immunotherapy.

Exposure to Ranitidine and Risk of Bladder Cancer: A Nested Case-Control Study.

INTRODUCTION: Ranitidine has been shown to contain the carcinogen N-nitrosodimethylamine and increase urinary N-nitrosodimethylamine in humans. We investigated whether ranitidine use is associated with increased bladder cancer risk. METHODS: A nested case-control study was conducted within the Primary Care Clinical Informatics Unit Research database which contains general practice records from Scotland. Bladder cancer cases, diagnosed between 1999 and 2011, were identified and matched with up to 5 controls (based on age, sex, general practice, and date of registration). Ranitidine, other histamine-2 receptor agonists, and proton pump inhibitors were identified from prescribing records. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using conditional logistic regression after adjusting for comorbidities and smoking. RESULTS: There were 3,260 cases and 14,037 controls. There was evidence of an increased risk of bladder cancer in ranitidine users, compared with nonusers (fully adjusted OR = 1.22; 95% CI 1.06-1.40), which was more marked with use for over 3 years of ranitidine (fully adjusted OR = 1.43; 95% CI 1.05-1.94). By contrast, there was little evidence of any association between proton pump inhibitor use and bladder cancer risk based on any use (fully adjusted OR = 0.98; 95% CI 0.88-1.11) or over 3 years of use (fully adjusted OR = 0.98; 95% CI 0.80-1.20). DISCUSSION: In this large population-based study, the use of ranitidine particularly long-term use was associated with an increased risk of bladder cancer. Further studies are necessary to attempt to replicate this finding in other settings.