Drug-drug interaction between clopidogrel and the proton pump inhibitors

Comparative efficiency and safety of potassium competitive acid blockers versus Lansoprazole in peptic ulcer: a systematic review and meta-analysis

Background: Lansoprazole, a proton-pump inhibitor (PPI), is the primary therapy for peptic ulcers (PU). Potassium competitive acid blockers (P-CAB) offer an alternative for acid suppression. However, the efficacy and safety of P-CABs versus lansoprazole in the management of PU has not been evaluated. Methods: Five databases were searched for randomized clinical trials in English until 31 August 2023. Data extraction provided outcome counts for ulcer healing, recurrent NSAID-related ulcer, and adverse events. The pooled effect, presented as rate difference (RD), was stratified by ulcer location, follow-up time, and the types of P-CAB, along with their corresponding 95% confidence intervals (95% CI). Results: The pooled healing rates of peptic ulcers were 95.3% (1,100/1,154) and 95.0% (945/995) for P-CABs and lansoprazole, respectively (RD: 0.4%, 95% CI: -1.4%-2.3%). The lower bounds of the 95% CI fell within the predefined non-inferiority margin of -6%. In subgroup analyses base on ulcer location, and follow-up time also demonstrated non-inferiority. The drug-related treatment-emergent adverse events (TEAEs) did not differ significantly among groups (RR: 0.997, 95% CI: 0.949-1.046, p = 0.893). However, P-CAB treatment was associated with an increased risk of the serious adverse events compared to lansoprazole (RR: 1.325, 95% CI: 1.005-1.747, p = 0.046). Conclusion: P-CABs demonstrated non-inferiority to lansoprazole in the management of peptic ulcer. The safety and tolerability profile are comparable, with similar TEAEs rates. However, P-CABs appear to have a higher risk of serious adverse events. Systematic Review Registration: https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=458361 Identifier: PROSPERO (No. CRD42023458361).

Focusing on Helicobacter pylori infection in the elderly

As a confirmed carcinogen, Helicobacter pylori (H. pylori) is the main cause of inflammatory diseases of the upper digestive tract and even gastric cancer. There is a high prevalence of H. pylori infection among the elderly population, which may cause adverse clinical outcomes. Particularly noteworthy is that guidelines or expert consensus presently available on H. pylori infection overlook the management of the elderly population as a special group. A brief overview of H. pylori in the elderly is as follows. The detection of H. pylori infection can be divided into invasive and non-invasive techniques, and each technique has its advantages and shortcomings. There may be more side effects associated with eradication treatment in elderly individuals, especially for the frail population. Physical conditions and risk-benefit assessments of the elderly should be considered when selecting therapeutic strategies for H. pylori eradication. Unless there are competing factors, elderly patients should receive H. pylori eradication regimens to finally reduce the formation of gastric cancer. In this review, we summarize the latest understanding of H. pylori in the elderly population to provide effective managements and treatment measures.

Efficacy and safety of concomitant use of proton pump inhibitors with aspirin-clopidogrel dual antiplatelet therapy in coronary heart disease: A systematic review and meta-analysis

Background: Proton pump inhibitors (PPIs) are usually prescribed to prevent gastrointestinal (GI) complications in patients receiving dual antiplatelet therapy (DAPT). This systematic review and meta-analysis aimed to explore the efficacy and safety of the concomitant use of PPIs with aspirin-clopidogrel DAPT in patients with Coronary heart disease (CHD). Method: The PubMed, Embase, Cochrane Library, and Web of Science databases were searched from inception to August 2022 for eligible studies. The adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated to evaluate the clinical outcomes. Subgroup analysis was conducted according to different PPI subtypes, populations, follow-up times and study types. This study was registered on PROSPERO (CRD42022332195). Results: A total of 173,508 patients from 18 studies [2 randomized controlled trials (RCTs), 3 post hoc analyses of RCTs, and 13 cohort studies] were included in this study. Pooled data revealed that coadministration of PPIs significantly increased the risk of major adverse cardiovascular events (MACEs) (HR = 1.15, 95% CI = 1.06-1.26, p = .001) and reduced the risk of gastrointestinal (GI) complications (HR = 0.44, 95% CI = 0.30-0.64, p < .0001). Subgroup analysis results showed that the esomeprazole users and patients with coronary stenting in the PPI group were associated with an increased risk of MACEs compared with the non-PPI group. The occurrence of MACEs in PPI users was more common than that in non-PPI users in long-term follow-up (≥12 months) studies and in the observational studies. There was no significant differences in the incidences of net clinical adverse events (NACEs), all-cause mortality, or cardiac death between the two groups. Conclusion: In patients with CHD, the concomitant use of PPIs with aspirin and clopidogrel was associated with a reduced risk of GI complications but could increase the rates of MACEs (particularly in patients receiving esomeprazole or with coronary stenting). There was no clear evidence of an association between PPI use and NACEs, all-cause mortality, or cardiac death. The results could have been affected by the follow-up time and study type. Further large-scale RCTs with long-term follow-up are needed.

Prevalence and Safety of Prescribing PPIs with Clopidogrel in Palestine

BACKGROUND

Proton pump inhibitors (PPIs) are commonly prescribed medications that are thought to increase the risk of cardiovascular events because they reduce the effectiveness of clopidogrel via shared hepatic pathways.

OBJECTIVE

This study examined the prevalence of concomitant prescribing of clopidogrel/PPI among patients diagnosed with acute coronary syndrome and the adverse cardiovascular event associated with this interaction.

METHODS

A retrospective cohort study was conducted by retrieving patient data from the Nat Health Insurance claims processor database in Palestine. Adults diagnosed with Acute Coronary Syndrome (ACS) from 2019 through 2021 who were prescribed clopidogrel or clopidogrel in combination with a PPI were included in the study. Endpoints were adverse cardiac events, including readmission for revascularization during the first year of treatment.

RESULTS

The study included 443 patients; the prevalence of prescribing concomitant clopidogrel with a PPI was 74.7%, whereas 49.2% were prescribed interacting PPI (omeprazole, esomeprazole, and lansoprazole). 59 (13.3%) of participants experienced a cardiovascular event within 1 year of starting therapy, including 27 (12.4%) patients who had a cardiovascular event while taking an interacting PPI. No significant association was found between PPI administration and increased CV event risk in patients receiving concomitant clopidogrel and PPIs therapy (p = 0.579).

CONCLUSION

In this study, we observed a high prevalence of prescribing a PPI in combination with clopidogrel, regardless of the FDA recommendations. No significant increase in cardiovascular events was observed in patients receiving concomitant clopidogrel and PPI therapy.

Use of proton pump inhibitor may be associated with progression of cerebral small vessel disease

Proton pump inhibitors (PPIs) are widely used for the treatment of gastrointestinal diseases. However, recent studies have shown that chronic PPI use is associated with the progression of endothelial senescence and cerebrovascular diseases. We hypothesized that PPI users might be vulnerable to fast progression of cerebral small vessel disease (SVD) with cumulative effects. Four hundred and eleven patients, who underwent brain magnetic resonance imaging, more than twice between January 2010 and December 2016 were screened. Patients aged < 50 years, and those who had concomitant diseases that might affect the progression of cerebral SVD were excluded. Baseline characteristics were collected. We evaluated the severity of SVD using the Fazekas score, the number of cerebral microbleeds (CMBs), and assessed the progression of SVD or CMBs based on the cumulative dose of PPIs. Among the included patients (N = 137), 39 were PPI ever-users. Univariate Cox regression analysis showed that PPI use was independently associated with the progression of Fazekas score only in the deep white matter hyperintensities (WMH) (hazard ratio [HR] 2.891, 95% confidence interval [CI] 1.210-6.906, P = 0.017). In multivariate Cox regression analysis, long-term PPI use was associated with a progression of Fazekas score in the deep WMH (HR 3.453, 95% CI 1.027-9.475, P = 0.045). However, PPI use was not associated with the progression of CMB. The present study results suggest that long-term use of PPIs is associated with the progression of deep cerebral WMH. Further research is needed using a large number of patients to validate this relationship.

Acute Multiple In-Stent Thromboses in a Patient With Clopidogrel-Fluconazole Interaction

Clopidogrel is an anti-platelet that exerts its function by selectively inhibiting the binding of adenosine di-phosphate (ADP) to the P2Y12 receptor. Fluconazole is a fungistatic agent that alters fungal cell membranes. Both of these drugs act on the cytochrome P450 2C19. We report the case of an 83-year-old male that presented two days following coronary angioplasty with stent thrombosis, following the concomitant use of clopidogrel and fluconazole. We aim to study the interaction between clopidogrel and fluconazole. We hypothesize that fluconazole decreases the therapeutic level of clopidogrel, requiring an increase in dosage to achieve the same anti-thrombotic effect.

Who gets prescriptions for proton pump inhibitors and why? A drug-utilization study with claims data in Bavaria, Germany, 2010-2018

PURPOSE

The German annual drug prescription-report has indicated overuse of proton pump inhibitors (PPIs) for many years; however, little was known about the characteristics of people using PPIs. This study aimed to provide comprehensive utilization data and describe frequencies of potential on- and off-label PPI-indications in Bavaria, Germany.

METHODS

Claims data of statutorily insured people from 2010 to 2018 were used. Defined daily doses (DDDs) of PPIs by type of drug, prevalence of PPI-use and DDDs prescribed per 1000 insured people/day were analyzed. For 2018, proportions of users and DDDs per 1000 insured people were calculated by age and sex. To elucidate changes in prescribing practices due to a suspected drug-drug interaction, we examined co-prescribing of clopidogrel and PPIs between 2010 and 2018. For PPI new users, sums of DDDs and frequencies of potential indications were examined.

RESULTS

PPI prescribing increased linearly from 2010 to 2016 and gradually decreased from 2016 to 2018. In 2018, 14.7% of women and 12.2% of men received at least one prescription, and 64.8 DDDs (WHO-def.) per 1000 insured people/day were prescribed. Overall, omeprazole use decreased over the observation period and was steadily replaced by pantoprazole, especially when co-prescibed with clopidogrel. An on-label PPI-indication was not reported at first intake in 52.0% of new users.

CONCLUSIONS

The utilization of prescribed PPIs has decreased since 2016. However, a large proportion of new PPI-users had no documentation of a potential indication, and the sums of DDDs prescribed often seemed not to comply with guidelines.

Helicobacter pylori Infection in Geriatric Patients: Current Situation and Treatment Regimens

Helicobacter pylori (H. pylori) has so far infected more than half the global population. It is the most important and controllable risk factor for gastric cancer. The elderly, who are at a higher incidence of the infection, are also commonly found to develop antibiotic resistance. The symptoms, diagnosis, clinical features (of gastric or extra-digestive diseases), and treatment of H. pylori infection in the elderly, are different from that in the non-elderly. Health conditions, including comorbidities and combined medication have limited the use of regular therapies in elderly patients. However, they can still benefit from eradication therapy, thus preventing gastric mucosal lesions and gastric cancer. In addition, new approaches, such as dual therapy and complementary therapy, have the potential to treat older patients with H. pylori infection.

Rabeprazole-amoxicillin dual therapy as first-line treatment for H pylori eradication in special patients: A retrospective, real-life study

BACKGROUND

The currently recommended quadruple regimens for Helicobacter pylori infection might not be appropriate for every patient, especially in elderly patients or those with multiple comorbidities.

OBJECTIVE

To evaluate the efficacy and safety of rabeprazole-amoxicillin dual therapy in H pylori-positive elderly patients or those with multiple comorbidities.

METHODS

From November 2013 to May 2017, the clinical data of H pylori-positive patients ≥60 years old or with multiple comorbidities were collected and reviewed. All patients were given rabeprazole 10 mg three times a day and amoxicillin 1000 mg thrice a day (RA dual therapy) for 14 days as first-line treatment. H pylori eradication was evaluated by ¹³ C-urea breath test 6 weeks after treatment. Adverse effects were recorded.

RESULTS

A total of 198 patients were enrolled, including 116 elderly patients and 82 patients with multiple comorbidities. Successful eradication was achieved in 90.9% (180/198, 95% CI: 86.1%-94.2%) patients. Adverse effects, which were mainly mild (referring to skin rash, abdominal pain, and diarrhea), occurred in 22 patients (22/198, 11.1%) and resolved spontaneously.

CONCLUSION

Dual therapy composed of rabeprazole and amoxicillin as a first-line treatment appears to be effective and safe for H pylori infection in elderly patients or those with multiple comorbidities. Additional studies are needed to optimize the regimen.

Potential proton pump inhibitor-related adverse effects

Proton pump inhibitors (PPIs) are one of the most common medications taken by patients worldwide. PPIs are used to treat acid-related disorders, including gastroesophageal reflux disease, peptic ulcer disease, Helicobacter pylori infection, and nonsteroidal anti-inflammatory drug/stress ulceration. For some of these diseases, long-term treatment is necessary. With such prolonged use, concern and investigation into potential adverse effects has increased. In addition, data are available regarding potential anticancer effects of PPIs, especially regarding solid tumors. The aim of this review is to assess the literature on PPIs with regard to common concerns, such as drug-drug interactions, the intestinal microbiome, dementia and central nervous system disease, and osteoporosis, as well as to highlight potential negative and positive impacts of the drug in cancer.

Precision medication: An illustrative case series guiding the clinical application of multi-drug interactions and pharmacogenomics

Precision medication entails selecting the precise medication, dose, and timing of administration. Multi-drug interactions and genetics significantly affect precision medication. In this article, we present two simulated cases for real-world applications of precision medication. Clinicians may need to acquire additional skills to apply the principles illustrated by these cases.

Comparison of prophylactic effect of UGIB and effects on platelet function between PPIs and H2RAs combined with DAPT: systematic review and meta-analysis

Objective

We compared prophylactic effects of proton pump inhibitors (PPIs) and histamine-2 receptor antagonists (H₂RAs) on upper gastrointestinal bleeding (UGIB) associated with dual antiplatelet therapy (DAPT) and explored this influence on platelet function.

Methods

Randomized controlled trials and cohort studies comparing PPIs with H₂RAs in adults receiving DAPT were collected from PubMed, EMBASE and Cochrane databases. Dichotomous data were pooled to obtain risk ratios (RRs) for UGIB, major adverse cardiovascular events (MACEs), poor responders to clopidogrel and rehospitalization, and continuous data were pooled to obtain mean differences (MDs) for P2Y₁₂ reaction units (PRUs), with 95% confidence intervals (CIs).

Results

Twelve clinical trials (n=3,301) met the inclusion criteria. Compared to H₂RAs, PPIs lessened UGIB (RR =0.16, 95% CI: 0.03–0.70), and there was no significant difference in the incidence of PRUs (MD =18.21 PRUs, 95% CI: −4.11–40.54), poor responders to clopidogrel (RR =1.21, 95% CI: 0.92–1.61), incidence of MACEs (RR =0.89, 95% CI: 0.45–1.75) or rehospitalization (RR =1.76, 95% CI: 0.79–3.92). Subgroup analysis confirmed fewer PRUs in the H₂RAs group compared to the omeprazole group (2 studies, n=189, MD =31.80 PRUs, 95% CI: 11.65–51.96). However, poor responder data for clopidogrel and MACEs might be unreliable because few studies of this kind were included.

Conclusion

Limited evidence indicates that PPIs were better than H₂RAs for prophylaxis of UGIB associated with DAPT and had no effect on platelet function. Further study is needed to confirm these observations.

Thienopyridines in Acute Coronary Syndrome

OBJECTIVE:

To evaluate the safety and efficacy of the thienopyridines in order to identify their current place in therapy for the treatment of acute coronary syndrome (ACS).

DATA SOURCES:

Literature was accessed through MEDLINE (1966-October 2010 week 1), EMBASE (1980–2010 week 40), and a bibliographic review of published articles using the search terms acute coronary syndrome, clopidogrel, and prasugrel. Articles were limited to clinical trials conducted in humans and published in the English language.

STUDY SELECTION AND DATA EXTRACTION:

Head-to-head clinical trials evaluating the safety and efficacy of the thienopyridines in patients with ACS were critically reviewed. Trials evaluating ticlopidine were excluded due to its limited clinical use.

DATA SYNTHESIS:

Thienopyridines are an integral part of the treatment of ACS. Prior to the approval of prasugrel, clopidogrel was considered the agent of choice due to safety concerns associated with ticlopidine. A randomized controlled trial comparing prasugrel and clopidogrel has demonstrated superior efficacy with prasugrel, and post hoc analyses suggest additional benefit with prasugrel is derived in patients with ST-segment elevation myocardial infarction and patients with diabetes. However, safety concerns exist linking prasugrel with an increased risk of bleeding, which diminishes its advantage in elderly patients, underweight patients, and those with a history of stroke. Pharmacokinetic and pharmacodynamic studies discussing differences in response variability, platelet inhibition, interactions with proton pump inhibitors, and genetic factors between the thienopyridines are numerous, although more clinical data are needed to determine clinical implications.

CONCLUSIONS:

Clinical trial data have suggested prasugrel is superior to clopidogrel at preventing ischemic events in patients with ACS undergoing percutaneous coronary intervention. However, this coincides with an increased risk of bleeding. Clinicians must carefully interpret the current evidence, including limitations in study design and pharmacologic differences between agents, in order to balance the risks and benefits as new data become available.

Proton-pump inhibitors adverse effects: a review of the evidence and position statement by the Sociedad Española de Patología Digestiva

INTRODUCTION

In the last few years a significant number of papers have related the use of proton-pump inhibitors (PPIs) to potential serious adverse effects that have resulted in social unrest.

OBJECTIVE

The goal of this paper was to provide a literature review for the development of an institutional position statement by Sociedad Española de Patología Digestiva (SEPD) regarding the safety of long-term PPI use.

MATERIAL AND METHODS

A comprehensive review of the literature was performed to draw conclusions based on a critical assessment of the following: a) current PPI indications; b) vitamin B12 deficiency and neurological disorders; c) magnesium deficiency; d) bone fractures; e) enteric infection and pneumonia; f) interactions with thienopyridine derivatives; e) complications in cirrhotic patients.

RESULTS

Current PPI indications have remained unchanged for years now, and are well established. A general screening of vitamin B12 levels is not recommended for all patients on a PPI; however, it does seem necessary that magnesium levels be measured at therapy onset, and then monitored in subjects on other drugs that may induce hypomagnesemia. A higher risk for bone fractures is present, even though causality cannot be concluded for this association. The association between PPIs and infection with Clostridium difficile is mild to moderate, and the risk for pneumonia is low. In patients with cardiovascular risk receiving thienopyridines derivatives it is prudent to adequately consider gastrointestinal and cardiovascular risks, given the absence of definitive evidence regardin potential drug-drug interactions; if gastrointestinal risk is found to be moderate or high, effective prevention should be in place with a PPI. PPIs should be cautiously indicated in patients with decompensated cirrhosis.

CONCLUSIONS

PPIs are safe drugs whose benefits outweigh their potential side effects both short-term and long-term, provided their indication, dosage, and duration are appropriate.

Histamine-2 Receptor Antagonist Cannot Prevent Recurrent Peptic Ulcers in Patients With Atherosclerotic Diseases Who Receive Platelet ADP Receptor Antagonist Monotherapy: A Randomized-Controlled, Double-Blind, and Double-Dummy Trial

OBJECTIVES

Proton pump inhibitor can effectively prevent recurrent peptic ulcers among atherosclerotic patients receiving clopidogrel monotherapy. However, the interaction between proton pump inhibitors and clopidogrel has raised concerns over the safety of combined use of the two medicines in clinical practice. The aims of this randomized-controlled, double-blind and double-dummy trial were to investigate the efficacy of histamine-2 receptor antagonist (H2RA) in the prevention of recurrent peptic ulcer in patients undergoing thienopyridine monotherapy.

METHODS

From January 2012 to 2016, long-termed thienopyridine users with a peptic ulcer history who did not have peptic ulcers at initial endoscopy were randomly assigned to receive either famotidine (40 mg, before bedtime) or placebo (before bedtime) for 6 months. Follow-up endoscopy was performed at the end of the 6th month and whenever dyspepsia, hematemesis, or melena occurred.

RESULTS

The cumulative incidence of recurrent peptic ulcer during the 6-month period was 7.0% in famotidine group (n=114) and 11.4% in the placebo group (n=114). The two patient groups had comparable cumulative incidence of peptic ulcer (difference, 4.4%; 95% confidence interval (CI), -11.7 to 2.9%; P=0.239). Additionally, there was no difference in the cumulative incidence of ulcer bleeding (2.6% vs. 1.8%; difference, 0.8%; 95% CI, -0.6 to 2.4%, P=1.000) between famotidine and placebo groups. However, the former had a lower incidence of gastroduodenal erosion than the latter (21.1% vs. 36.8%; difference, 15.7%; 95% CI, -27.3 to -4.1%; P=0.013).

CONCLUSIONS

Famotidine cannot decrease the incidence of peptic ulcer or ulcer bleeding in thienopyridine users with atherosclerotic disease and a history of peptic ulcer.

Acute hepatitis associated with clopidogrel: a case report and review of the literature

Drug-induced hepatotoxicity is a common cause of acute hepatitis, and the recognition of the responsible drug may be difficult. We describe a case of clopidogrel-related acute hepatitis. The diagnosis is strongly suggested by an accurate medical history and liver biopsy. Reports about cases of hepatotoxicity due to clopidogrel are increasing in the last few years, after the increased use of this drug. In conclusion, we believe that physicians should carefully consider the risk of drug-induced hepatic injury when clopidogrel is prescribed.

Point-of-care platelet reactivity determination with VerifyNow-P2Y12 following administration of clopidogrel or prasugrel: data from a real-world, clinical care inpatient setting

OBJECTIVES

To describe VerifyNow-P2Y12 (VN-P2Y12, Accumetrics, San Diego, CA) results from patients treated with either clopidogrel or prasugrel who were seeking care in a hospital setting.

BACKGROUND

VN-P2Y12 is a point-of-care device that measures platelet reactivity to adenosine diphosphate. Past assessments of thienopyridine therapy utilizing VN-P2Y12 have largely come from clinical trial settings. There are limited data from real-world settings.

METHODS

Electronic medical record data from Huntsville Hospital (Huntsville, AL) for those who underwent VN-P2Y12 testing for clopidogrel or prasugrel between January 1, 2009 and October 31, 2010 were analyzed. The VN-P2Y12 data included P2Y12 reaction units (PRUs) and device-reported percentage of inhibition. Descriptive analyses were conducted with t tests, and a logistic regression model was estimated to assess the association between patient characteristics and the likelihood of platelet nonresponse.

RESULTS

In total, 2882 tests (2476 with clopidogrel and 406 with prasugrel) were analyzed. For clopidogrel and prasugrel, respectively, mean PRU standard deviation (SD) was 206 (90) and 107 (93; P < 0.0001) and mean % inhibition (SD) was 31% (26%) and 63% (31%; P < 0.0001). Treatment with clopidogrel alone (odds ratio [OR] = 5.25; P < 0.0001), being non-Caucasian (OR = 1.48; P = 0.0440), obese (OR = 1.49; P = 0.0010), anemic (OR = 3.29; P < 0.0001), diabetic (OR = 1.75; P < 0.0001), and having a history of myocardial infarction (OR = 1.57; P < 0.0001) were significant predictors of having PRU ≥ 235.

CONCLUSION

This real-world data analysis shows results that are consistent with clinical trial results, namely that compared with clopidogrel, prasugrel is associated with significantly lower PRU and greater percentage of inhibition, regardless of age, race, gender, diabetes, obesity, or proton pump inhibitor use.

Approach to Helicobacter pylori infection in geriatric population

The prevalence of Helicobacter pylori (H. pylori) infection and its complications increase with age. The majority of infected individuals remain asymptomatic throughout the life but 10%-20% develops peptic ulcer disease and 1% gastric malignancies. The incidence of ulcers and their complications are more common in the older population resulting in higher hospitalization and mortality rates. The increased use of medications causing gastric mucosal damage and the decreased secretion of protective prostaglandins in elderly are major factors increasing gastric mucosal sensitivity to the destructive effects of H. pylori. Due to higher prevalence of gastrointestinal (GI) malignancies, upper GI endoscopy is mostly preferred in elderly for the diagnosis of infection. Therefore, “endoscopy and treat” strategy may be more appropriate instead of “test and treat” strategy for dyspeptic patients in older age. Urea breath test and stool antigen test can be used for control of eradication, except for special cases requiring follow-up with endoscopy. The indications for treatment and suggested eradication regimens are similar with other age groups; however, the eradication failure may be a more significant problem due to high antibiotic resistance and low compliance rate in elderly. Multidrug usage and drug interactions should always be considered before starting the treatment. This paper reviews briefly the epidemiology, diagnosis, disease manifestations, and treatment options of H. pylori in the geriatric population.

Implications of over-the-counter proton pump inhibitors for patient counseling by pharmacists

The article reviews the literature on the role of the pharmacist in patient counseling and discusses how that role may apply to patients with frequent heartburn who are seeking an over-the-counter (OTC) treatment. Searches of the National Library of Medicine PubMed database were conducted using the terms "heartburn," "nonprescription," "therapy," "pharmacist," and "counseling," supplemented by additional searches on counseling for prescription products, and by the author's knowledge of pharmacy practice and the scientific literature. Accurate recognition of the signs of heartburn are an important first step in counseling a patient on the appropriate OTC medication; immediate referral to a health care provider is mandatory if cardiac pain or certain gastrointestinal symptoms are present. When counseling a patient about treatments for heartburn, the pharmacist should practice effective listening in an environment that is conducive to communication by the patient. Proton pump inhibitors are effective for the treatment of heartburn; the histamine2 receptor antagonists and antacids should also be considered for appropriate patients. Adverse events have been noted with proton pump inhibitors; however, overall the benefits significantly outweigh the risks and problems are unlikely to arise during the 2-week duration of OTC treatment of heartburn. Pharmacists can provide valuable services to patients with frequent heartburn, particularly with regard to counseling about the condition and appropriate OTC therapy. The availability of numerous OTC products, including antacids, histamine2 receptor antagonists, and proton pump inhibitors, enables pharmacists to fulfill an important clinical role and improve patient satisfaction.

[Effect of drug interaction between clopidogrel and omeprazole in hospital readmision of patients by a recurrent acute coronary syndrome: a case-control study]

Objetivo

Evaluar el efecto de la interacción clopidogrel-omeprazol en el reingreso hospitalario de pacientes por recidiva de síndrome coronario agudo (SCA)

Diseño

Estudio de casos y controles

Emplazamiento

IPS Universitaria Clínica León XIII, Medellín, Colombia.

Participantes

Se seleccionaron a partir de una población prevalente, entre 2009-2010, pacientes con uso de clopidogrel de forma ambulatoria (menor a un año y superior a 30 días), y la estancia hospitalaria por un SCA o la presencia de un SCA previo.

Medidas principales

Un paciente-caso se definió como aquel que presentó una recidiva de SCA y un paciente-control se definió como aquel que no presentó recidiva de SCA. Ambos grupos utilizaron ambulatoriamente clopidogrel debido al SCA previo. Como factor de riesgo se definió la utilización conjunta de omeprazol y clopidogrel ambulatoriamente.

Resultados

Durante el estudio se formuló clopidogrel a 1.680 pacientes. En este grupo se identificaron 50 casos readmitidos con SCA y 76 controles. No se encontró asociación estadísticamente significativa entre el uso de clopidogrel-omeprazol y un mayor riesgo de reingreso hospitalario por SCA (OR: 1,05; IC 95%: 0,516-2,152; p = 0,8851).

Conclusiones

En este pequeño grupo de pacientes con SCA previo, la utilización simultánea de clopidogrel con omeprazol no aumenta el riesgo de un reingreso hospitalario por recurrencia de este tipo de evento coronario.

Proton pump inhibitors and clopidogrel: an association to avoid?

Dual antiplatelet therapy with aspirin and clopidogrel reduces cardiovascular events following an acute coronary syndrome or stent implantation, but the associated increased risk of gastro-intestinal bleeding often leads to the co-administration of proton pump inhibitors (PPIs). PPIs have been shown to decrease antiplatelet effects of clopidogrel ex vivo, raising concerns about the cardiovascular safety of this drug combination. Clinical trials investigating PPI-clopidogrel interactions have provided conflicting results and are all subject to methodological critiques. The much desired and much needed prospective, double-bind, randomized, placebo-controlled trials with adequate follow-up and sample size have not yet been performed. Indeed, the Clopidogrel and the Optimization of GI Events Trial, which would have had such characteristics, was stopped prematurely. As a consequence, the question of the PPI-clopidogrel interaction is still unresolved, and clinical consequences cannot be excluded. At this time such combination therapy should, therefore, be provisionally advocated only for patients at high risk of bleeding (prior upper gastro-intestinal bleeding, advanced age, concomitant use of warfarin, steroidal or non-steroidal anti-inflammatory drugs and Helicobacter pylori infection) and avoiding PPIs with strong affinity for cytochrome CYP2C19, such as omeprazole and esomeprazole.

Pharmacokinetic drug interaction profile of omeprazole with adverse consequences and clinical risk management

BACKGROUND

Omeprazole, a proton pump inhibitor (PPI), is widely used for the treatment of dyspepsia, peptic ulcer, gastroesophageal reflux disease, and functional dyspepsia. Polypharmacy is common in patients receiving omeprazole. Drug toxicity and treatment failure resulting from inappropriate combination therapy with omeprazole have been reported sporadically. Systematic review has not been available to address the pharmacokinetic drug-drug interaction (DDI) profile of omeprazole with adverse consequences, the factors determining the degree of DDI between omeprazole and comedication, and the corresponding clinical risk management.

METHODS

Literature was identified by performing a PubMed search covering the period from January 1988 to March 2013. The full text of each article was critically reviewed, and data interpretation was performed.

RESULTS

Omeprazole has actual adverse influences on the pharmacokinetics of medications such as diazepam, carbamazepine, clozapine, indinavir, nelfinavir, atazanavir, rilpivirine, methotrexate, tacrolimus, mycophenolate mofetil, clopidogrel, digoxin, itraconazole, posaconazole, and oral iron supplementation. Meanwhile, low efficacy of omeprazole treatment would be anticipated, as omeprazole elimination could be significantly induced by comedicated efavirenz and herb medicines such as St John's wort, Ginkgo biloba, and yin zhi huang. The mechanism for DDI involves induction or inhibition of cytochrome P450, inhibition of P-glycoprotein or breast cancer resistance protein-mediated drug transport, and inhibition of oral absorption by gastric acid suppression. Sometimes, DDIs of omeprazole do not exhibit a PPI class effect. Other suitable PPIs or histamine 2 antagonists may be therapeutic alternatives that can be used to avoid adverse consequences. The degree of DDIs associated with omeprazole and clinical outcomes depend on factors such as genotype status of CYP2C19 and CYP1A2, ethnicity, dose and treatment course of precipitant omeprazole, pharmaceutical formulation of object drug (eg, mycophenolate mofetil versus enteric-coated mycophenolate sodium), other concomitant medication (eg, omeprazole-indinavir versus omeprazole-indinavir-ritonavir), and administration schedule (eg, intensified dosing of mycophenolate mofetil versus standard dosing).

CONCLUSION

Despite the fact that omeprazole is one of the most widely prescribed drugs internationally, clinical professionals should enhance clinical risk management on adverse DDIs associated with omeprazole and ensure safe combination use of omeprazole by rationally prescribing alternatives, checking the appropriateness of physician orders before dispensing, and performing therapeutic drug monitoring.

Cardiovascular outcomes associated with concomitant use of clopidogrel and proton pump inhibitors in patients with acute coronary syndrome in Taiwan

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

Conflicting results have been reported regarding the increased risk of adverse outcomes in the concomitant use of clopidogrel and proton pump inhibitors (PPIs) compared with the use of clopidogrel alone.

WHAT THIS STUDY ADDS

Our study indicated no statistically significant increase in the risk of rehospitalization for acute coronary syndrome due to concurrent use of clopidogrel and PPIs in an Asian population with higher prevalence of CYP2C19 intermediate and poor metabolizers. Among all PPIs, only omeprazole was found to be statistically significantly associated with an increased risk of rehospitalization for acute coronary syndrome. AIMS Our study aimed to examine the impact of concomitant use of proton pump inhibitors (PPIs) with clopidogrel on the cardiovascular outcomes of patients with acute coronary syndrome (ACS). Furthermore, we sought to quantify the effects of five individual PPIs when used concomitantly with clopidogrel.

METHODS

We conducted a retrospective cohort study of patients who were newly hospitalized for ACS between 1 January 2006 and 31 December 2007 retrieved from the Taiwan National Health Insurance Research Database (NHIRD) and who were prescribed clopidogrel (n= 37 099) during the follow-up period. A propensity score technique was used to establish a matched cohort in 1:1 ratio (n= 5173 for each group). The primary clinical outcome was rehospitalization for ACS, while secondary outcomes were rehospitalization for percutaneous transluminal coronary angioplasty (PTCA) with stent, PTCA without stent and revascularization (PTCA or coronary artery bypass graft surgery) after the discharge date for the index ACS event.

RESULTS

The adjusted hazard ratio of rehospitalization for ACS was 1.052 (95% confidence interval, 0.971-1.139; P= 0.214) in the propensity score matched cohort. Among all PPIs, only omeprazole was found to be statistically significantly associated with an increased risk of rehospitalization for ACS (adjusted hazard ratio, 1.226; 95% confidence interval, 1.066-1.410; P= 0.004). Concomitant use of esomeprazole, pantoprazole, rabeprazole and lansoprazole did not increase the risk.

CONCLUSIONS

Our study indicated no statistically significant increase in the risk of rehospitalization for ACS due to concurrent use of clopidogrel and PPIs overall. Among individual PPIs, only omeprazole was found to be statistically significantly associated with increased risk of rehospitalization for ACS.

Role of CYP450 in Antiplatelet Therapy: Considerations for Patients at Risk for Further Cardiovascular or Cerebrovascular Problems

Objective:

To determine how interactions with cytochrome P450 ( CYP450) isoenzyme pathways may influence the selection of antiplatelet therapy in patients with cardiovascular and cerebrovascular disease.

Data Sources:

A MEDLINE search (1966-September 2012) was performed using the following MeSH search terms: clopidogrel, prasugrel, ticagrelor, aspirin, dipyridamole, drug interactions, polymorphism, cytochrome P450, platelets, platelet reactivity testing, and platelet function. In addition, reference citations were reviewed.

Study Selection and Data Extraction:

Selected studies analyzed the effects of CYP450 isoenzymes on the efficacy of antiplatelet therapy and potential drug-drug interactions.

Data Synthesis:

Antiplatelet therapy is pivotal in reducing the risk of acute coronary syndromes. Thienopyridines are commonly prescribed for antiplatelet drug therapy; however, a multitude of factors can influence their efficacy, given that thienopyridines require activation through CYP450 isoenzymes. Genetic polymorphisms in CYP450 isoenzymes and the susceptibility of drug-drug interactions mediated through the CYP450 system have led to variability in antiplatelet response. Two factors in particular have been prime targets in elucidating the role of CYP450 isoenzymes on thienopyridine activity and bioavailability: CYP2C19*2 polymorphisms and drug interactions with proton pump inhibitors. Additionally, many studies have surfaced in an attempt to quantify a patient's response to antiplatelet therapy but, to date, none has determined whether platelet reactivity testing is mandatory prior to initiation of therapy or whether it correlates with clinical efficacy. This review spotlights the pharmacokinetic and pharmacodynamic influences that CYP450 isoenzymes exert on antiplatelet therapies and attempts to categorize the role of platelet reactivity testing in determining the clinical significance of drug interactions.

Conclusions:

Suboptimal responses to antiplatelet therapy may occur because of interactions with CYP450 isoenzyme pathways. Further studies are warranted to clarify the impact of genetic polymorphisms and drug-drug interactions on clinical outcomes in patients with cardiovascular/cerebrovascular disease.

Impact of proton pump inhibitors or famotidine on the antiplatelet actions during dual-antiplatelet therapy in Japanese patients

BACKGROUND

It has been reported that the antiplatelet action becomes attenuated when a proton pump inhibitor is used in combination with clopidogrel.

PURPOSE

The effect of an antacid causing platelet aggregation during the administration of clopidogrel was investigated.

SUBJECTS AND METHODS

The subjects consisted of 265 patients with coronary artery disease. Platelet aggregation function testing (light transmittance aggregometry) was conducted while aspirin and clopidogrel 75 mg were taken orally and the minimum concentration of aggregation induction platelet aggregation threshold index was measured. The ADP-PATI, measured with ADP as the inducing substance, was compared and investigated according to the type of concomitantly used antacid.

RESULT

The results of the ADP-PATI were: control group: 3.47 ± 0.95 μM (N = 67), famotidine group: 3.80 ± 0.52 μM (N = 32), rabeprazole group: 3.43 ± 0.93 μM (N = 87), lansoprazole group: 3.28 ± 1.04 μM (N = 63) and omeprazole group: 3.33 ± 0.81 μM (N = 16). No statistically significant difference was observed regarding the ADP-PATI of respective groups compared to the control group.

CONCLUSION

The concomitant use of famotidine, rabeprazole, lansoprazole, and omeprazole did not affect the antiplatelet action of clopidogrel in Japanese patients.

Relative Copy Number Variations of CYP2C19 in South Indian Population

CYP2C19 is a polymorphic enzyme involved in the metabolism of clinically important drugs. Genotype-phenotype association studies of CYP2C19 have reported wide ranges in the metabolic ratios of its substrates. These discrepancies could be attributed to the variations in the promoter region and this aspect has been reported recently. The observations in the recent reports on the influence of promoter region variants on the metabolism of CYP2C19 substrates might also have been influenced by the copy number variations of CYP2C19. In this paper, we describe copy number variations of CYP2C19 using real-time polymerase chain reaction by comparative Ct method. No copy number variations were observed in the south Indian population indicating the observed discrepancies in genotype-phenotype association studies might be due to the regulatory region polymorphisms as reported earlier.

Preventive and therapeutic strategies for gastrointestinal injury associated with antiplatelet therapy

Antiplatelet therapy is the basic therapy for cardiovascular diseases and is widely used in clinical practice. It can cause damage to the gastrointestinal tract and induce severe events such as gastrointestinal bleeding. It is very important for clinicians to prevent and treat this side effect in patients taking low-dose aspirin and clopidogrel. In this paper we discuss the mechanism, prevention and treament of gastrointestinal injury caused by aspirin and clopidogrel, and introduce the consensus recommendations on reducing the gastrointestinal risk of antiplatelet therapy.

New look at antiplatelet agent-related peptic ulcer: an update of prevention and treatment

Patients taking antiplatelet agents for the prevention of cardiovascular diseases who develop gastrointestinal bleeding represent a serious challenge in clinical practice. The initial step in reducing gastrointestinal risk of antiplatelet therapy is to assess whether the patient has a continued need for antiplatelet therapy. The next step is to eliminate the risk factors that may place the patient at increased gastrointestinal risk. In the management of bleeding ulcer patients with high-risk stigmata of recent hemorrhage, resuming antiplatelet agents at 3-5 days after the last dosing is a reasonable strategy. However, patients with low-risk stigmata can keep taking antiplatelet agents immediately following endoscopy. In the management of aspirin-related uncomplicated peptic ulcers in patients requiring antiplatelet therapies, continuing aspirin plus a powerful proton pump inhibitor is the choice of treatment. Patients who require antiplatelet agents for the prevention of cardiovascular diseases should be tested and treated for Helicobacter pylori infection before starting antiplatelet therapy. Additionally, those with high risks for upper gastrointestinal bleeding should receive co-therapy with a gastroprotective drug, preferably a proton pump inhibitor at standard dose. H2-receptor antagonist can significantly reduce upper gastrointestinal bleeding risk in patients taking low-dose aspirin but it is ineffective in the prevention of upper gastrointestinal bleeding in clopidogrel users. Although several retrospective studies reported that patients prescribed clopidogrel who also took proton pump inhibitors had significant increases in cardiovascular events, the current evidence from a prospective randomized trial does not justify a conclusion that proton pump inhibitors are associated with cardiovascular events among clopidogrel users.

A comprehensive comparative review of adenosine diphosphate receptor antagonists

INTRODUCTION

Thrombosis risk necessitates dual antiplatelet therapy with aspirin and an adenosine diphosphate (ADP) receptor antagonist, in patients who have acute coronary syndrome. Current guidelines emphasize the critical role of dual antiplatelet therapy in both medical management and invasive strategy, especially in patients undergoing percutaneous coronary intervention. With the availability of multiple ADP-receptor antagonists, it is crucial to select the most appropriate agent for each patient.

AREAS COVERED

The pertinent trials were identified through a MEDLINE search, in addition to a manual search from the articles retrieved. This review examines the differences between clopidogrel, prasugrel and ticagrelor in terms of their pharmacological/pharmacokinetic properties, clinical efficacy, drug interactions and safety parameters.

EXPERT OPINION

Prasugrel and ticagrelor exhibit greater platelet inhibition and superior efficacy compared with clopidogrel, at the expense of higher bleeding risk. Prasugrel and ticagrelor should be preferred over clopidogrel in patients who are at a high risk of thrombotic events with low risk of bleeding. Additionally, these two agents may offer advantage over clopidogrel in those patients who might have risk for drug resistance due to CYP2C19 polymorphism. In selecting the ideal agent for patients, clinicians should tailor the antiplatelet regimen by considering individual risk factors and medication characteristics.

Cytochrome P450 2C19 polymorphism is associated with reduced clopidogrel response in cerebrovascular disease

PURPOSE

Clopidogrel is a prodrug that requires transformation into an active metabolite by cytochrome P450 (CYP) in the liver in order to irreversibly inhibit the P2Y12 adenosine diphosphate platelet receptor. CYP2C19 polymorphism has been reported to correlate with reduced antiplatelet activity of clopidogrel in coronary artery disease. We assessed the association between CYP2C19 polymorphism and clopidogrel resistance in patients with cerebrovascular disease.

MATERIALS AND METHODS

We retrospectively gathered data from patients who experienced cerebrovascular disease, received clopidogrel, and were tested for clopidogrel resistance and CYP2C19 polymorphism. Clopidogrel resistance was tested by the VerifyNow P2Y12 system, and the CYP2C19 polymorphism was tested by the Seeplex CYP2C19 ACE Genotyping system. Clopidogrel resistance was expressed in P2Y12 reaction units (PRU) and percent inhibition. High PRU and low percent inhibition suggests clopidogrel resistance. CYP2C19 polymorphisms were expressed as extensive, intermediate, and poor metabolizers. Clopidogrel resistance was assessed according to the subgroup of CYP2C19 polymorphism.

RESULTS

A total of 166 patients were evaluated. The PRU values of extensive CYP2C19 metabolizers (195.0±84.9) were significantly lower than those of intermediate and poor metabolizers (237.9±88.0, 302.2±58.9). The percent inhibition of extensive metabolizers (44.6±21.8) was significantly higher than that of intermediate and poor metabolizers (30.5±21.5, 14.0±13.4).

CONCLUSION

Intermediate and poor metabolizing CYP2C19 polymorphism is associated with reduced clopidogrel antiplatelet activity in patients with cerebrovascular disease. The clinical implications of this finding require further investigation.

Cytochrome P450-mediated cardiovascular drug interactions

INTRODUCTION

There are numerous drug-drug interactions (DDIs) related to cardiovascular medications and many of these are mediated via the cytochrome P450 (CYP) system. Some of these may lead to serious adverse events and it is, therefore, essential that clinicians are aware of the important interactions that occur.

AREAS COVERED

An extensive literature search was performed to analyze the CYP-mediated cardiovascular DDIs that lead to a loss of efficacy or potential toxicity. Cardiovascular drugs may be victims or act as perpetrators of DDIs. The paper analyzes CYP-mediated drug interactions concerning anticoagulants, antiplatelet agents, antiarrhythmics, β-blockers, calcium antagonists, antihypertensive medications, lipid-lowering drugs and oral antidiabetic agents.

EXPERT OPINION

Cardiovascular DDIs involving the CYP system are numerous. Additionally, the spectrum of drugs prescribed is constantly changing, particularly with cardiovascular diseases and it is not necessarily the case that drugs that had shown safety earlier will always show safety. Clinicians are encouraged to develop their knowledge of CYP-mediated DDIs so that they can choose safe drug combination regimens, adjust drug dosages appropriately and conduct therapeutic drug monitoring for drugs with narrow therapeutic indices.

[Antiplatelet agents and proton pump inhibitors. How can the risk-benefit balance be optimized in patients at risk for cardiovascular disease and gastrointestinal bleeding?]

Antiplatelet agents are routinely used in both primary and secondary prevention of cardiovascular events. The development of new antiplatelet agents and the strong growth of interventional cardiology have led to this therapy being more widely prescribed and for longer periods. The most important secondary effect is the rise in the incidence of hemorrhagic complications, the most prevalent being gastrointestinal bleeding. In this context, the balance between the cardiovascular benefits and bleeding risk of these agents must be optimized. This review provides specific management recommendations and highlights important practical aspects related to antiplatelet therapy, including the interaction between clopidogrel and proton pump inhibitors. The benefits and hazards in distinct clinical settings are outlined within the context of optimizing the balance between the cardiovascular benefits and bleeding risk of antiplatelet therapy.

Clinical evidence of interaction between clopidogrel and proton pump inhibitors

Clopidogrel is approved for reduction of atherothrombotic events in patients with cardiovascular (CV) and cerebrovascular disease. Dual antiplatelet therapy with aspirin and clopidogrel decreases the risk of major adverse cardiac events after acute coronary syndrome or percutaneous coronary intervention, compared with aspirin alone. Due to concern about gastrointestinal bleeding in patients who are receiving clopidogrel and aspirin therapy, current guidelines recommend combined use of a proton pump inhibitor (PPI) to decrease the risk of bleeding. Data from previous pharmacological studies have shown that PPIs, which are extensively metabolized by the cytochrome system, may decrease the ADP-induced platelet aggregation of clopidogrel. Results from retrospective cohort studies have shown a higher incidence of major CV events in patients receiving both clopidogrel and PPIs than in those without PPIs. However, other retrospective analyses of randomized clinical trials have not shown that the concomitant PPI administration is associated with increased CV events among clopidogrel users. These controversial results suggest that large specific studies are needed. This article reviews the metabolism of clopidogrel and PPIs, existing clinical data regarding the interaction between clopidogrel and PPIs, and tries to provide recommendations for health care professionals.

Review article: proton pump inhibitors with clopidogrel--evidence for and against a clinically-important interaction

BACKGROUND

The treatment of acute coronary syndromes involves a combination of antiplatelet therapies. Proton pump inhibitors are frequently recommended for patients receiving clopidogrel in addition to aspirin, to minimise the risk of bleeding. Several studies have shown that proton pump inhibitors can affect the platelet inhibitory effects of clopidogrel. However, the data on whether this has an effect on clinical outcomes are conflicting and a definitive answer is still awaited.

AIM

To provide an overview of the evidence for the pharmacological interaction between proton pump inhibitors and clopidogrel and to discuss whether this interaction translates into adverse clinical outcomes. Despite recent developments, clear consensus is lacking.

METHODS

A search of the published literature combined with the authors' knowledge of the field.

RESULTS

There is evidence to show that proton pump inhibitors can influence the pharmacodynamics of clopidogrel, but the data suggesting clinical effects are weak and conflicting. Supporting a clinically important interaction are four retrospective studies including over 11,000 patients prescribed both clopidogrel and a proton pump inhibitor. Evidence against a clinically important interaction is derived from over 18,000 patients from seven studies, including the only prospective trial to examine the potential interaction. Confounding variables are relevant and prospective clinical evidence is lacking.

CONCLUSIONS

Proton pump inhibitors offer clear protection and the concern over clinically relevant interactions with clopidogrel is biologically plausible, but not yet proven.

Clinical outcomes in patients with the concomitant use of clopidogrel and proton pump inhibitors after percutaneous coronary intervention: an analysis from the Guthrie Health Off-Label Stent (GHOST) investigators

BACKGROUND

The concomitant use of proton pump inhibitors (PPIs) with clopidogrel is suspected to be associated with an adverse impact on clinical outcomes in patients with coronary artery disease. We sought to evaluate whether the use of PPIs with clopidogrel was associated with worse clinical outcomes after percutaneous coronary intervention (PCI) compared with the use of clopidogrel alone.

METHODS AND RESULTS

We studied 2651 consecutive patients discharged alive after coronary stenting for stable or unstable coronary artery disease between 2001 and 2007. All patients received aspirin indefinitely and a thienopyridine for 1 to 12 months. Patients were categorized into 2 groups: those taking a PPI [PPI (+), n=751] and those not taking a PPI [PPI (-), n=1900] at discharge. The primary end points were the 6-month incidence of major adverse cardiovascular events (MACE) (composite of death, myocardial infarction, target vessel revascularization, and stent thrombosis) and net adverse clinical events (NACE) (composite of MACE and thrombolysis in myocardial infarction major or minor bleeding), which were evaluated using propensity-adjusted Cox regression analysis. In addition, propensity-matched analysis was performed in 685 pairs of patients. The PPI (+) group was older and had more comorbid conditions than the PPI (-) group. In propensity-adjusted as well as propensity-matched analyses, the use of PPIs was not associated with an increased risk of MACE or NACE.

CONCLUSIONS

The use of PPIs with dual antiplatelet therapy was not associated with any adverse influence on MACE or NACE after PCI.