Influence of non-steroidal anti-inflammatory drugs on renal function and 24h ambulatory blood pressure-reducing effects of enalapril and nifedipine gastrointestinal therapeutic system in hypertensive patients

Effect of aspirin on blood pressure in hypertensive patients: a systematic review and meta-analysis

INTRODUCTION

Aspirin is widely used for secondary prevention in patients with hypertension. However, previous studies mainly focused on the preventive effects of aspirin, and there has been a lack of reliable evidence on whether taking aspirin affects blood pressure This study aimed to investigate whether aspirin would affect the blood pressure in patients with hypertension.

METHODS

PubMed, Cochrane database, Embase, Scopus and Medline databases were searched until September 2023. For continuous variables (e.g., blood pressure reduction), the mean difference (MD) was selected as the effect magnitude indices. We used the Cochrane Collaboration's Risk of Bias tool to assess the risk of bias.

RESULT

A total of five studies were included, comprising 20,312 patients. We found that aspirin did not affect SBP (MD = -0.78, 95% CI: - 2.41, 0.84). A similar result was found for DBP (MD = -0.86, 95% CI: - 2.14, 0.42).

CONCLUSION

This study showed no significant difference in blood pressure between the aspirin and control groups, suggesting that aspirin does not affect blood pressure.

Development and Characterization of Different Dosage Forms of Nifedipine/Indomethacin Fixed-Dose Combinations

Studies have shown that 40 individuals out of 100,000 are diagnosed with rheumatoid arthritis (RA) yearly, with a total of 1.3 million in the United States. Furthermore, the impact of RA in some cases can extend to cardiovascular diseases (CVD), as the studies showed that 84% of RA patients are at risk of developing hypertension. This study aims to design and develop different dosage forms (capsule-in-capsule and three-dimensional (3D) printed tablet) of nifedipine/indomethacin fixed-dose combination (FDC). The hot-melt extrusion (HME) was utilized alone and with fused deposition modeling (FDM) techniques The developed dosage forms were intended to provide delayed-extended and immediate release profiles for indomethacin and nifedipine, respectively. FDC dosage forms were successfully developed and characterized. Nifedipine formulations showed significant improvement in release profiles, having 94% of the drug release at 30 minutes compared with pure nifedipine, which had a percent release of 2%. Furthermore, the release of indomethacin was successfully delayed at a pH of 1.2 and extended at a pH of 6.8. Differential scanning calorimetry results showed endothermic crystalline peaks at 165 °C and 176 °C for indomethacin and nifedipine, respectively. Moreover, the thermal analysis of all formulations showed the absence of the endothermic peaks indicating complete solubilization of indomethacin and nifedipine in the polymeric carriers. All formulations had post-processing drug content in the range of 95% to 98%. Moreover, results from the stability study showed that all formulations were able to remain chemically and physically stable with no signs of recrystallization or degradation. The designed FDC dosage forms could improve the quality of life by enhancing patient compliance and preventing the need for polypharmacy.

Antiplatelet agents and anticoagulants for hypertension

BACKGROUND

The main complications of elevated systemic blood pressure (BP), coronary heart disease, ischaemic stroke, and peripheral vascular disease, are related to thrombosis rather than haemorrhage. Therefore, it is important to investigate if antithrombotic therapy may be useful in preventing thrombosis-related complications in patients with elevated BP.

OBJECTIVES

To conduct a systematic review of the role of antiplatelet therapy and anticoagulation in patients with elevated BP, including elevations in systolic or diastolic BP alone or together. To assess the effects of antiplatelet agents on total deaths or major thrombotic events or both in these patients versus placebo or other active treatment. To assess the effects of oral anticoagulants on total deaths or major thromboembolic events or both in these patients versus placebo or other active treatment.

SEARCH METHODS

The Cochrane Hypertension Information Specialist searched the following databases for randomised controlled trials (RCTs) up to January 2021: the Cochrane Hypertension Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL; 2020, Issue 12), Ovid MEDLINE (from 1946), and Ovid Embase (from 1974). The World Health Organization International Clinical Trials Registry Platform and the US National Institutes of Health Ongoing Trials Register (ClinicalTrials.gov) were searched for ongoing trials.  SELECTION CRITERIA: RCTs in patients with elevated BP were included if they were ≥ 3 months in duration and compared antithrombotic therapy with control or other active treatment.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data for inclusion criteria, our prespecified outcomes, and sources of bias. They assessed the risks and benefits of antiplatelet agents and anticoagulants by calculating odds ratios (OR), accompanied by the 95% confidence intervals (CI). They assessed risks of bias and applied GRADE criteria.  MAIN RESULTS: Six trials (61,015 patients) met the inclusion criteria and were included in this review. Four trials were primary prevention (41,695 patients; HOT, JPAD, JPPP, and TPT), and two secondary prevention (19,320 patients, CAPRIE and Huynh). Four trials (HOT, JPAD, JPPP, and TPT) were placebo-controlled and two studies (CAPRIE and Huynh) included active comparators. Four studies compared acetylsalicylic acid (ASA) versus placebo and found no evidence of a difference for all-cause mortality (OR 0.97, 95% CI 0.87 to 1.08; 3 studies, 35,794 participants; low-certainty evidence). We found no evidence of a difference for cardiovascular mortality (OR 0.98, 95% CI 0.82 to 1.17; 3 studies, 35,794 participants; low-certainty evidence). ASA reduced the risk of all non-fatal cardiovascular events (OR 0.63, 95% CI 0.45 to 0.87; 1 study (missing data in 3 studies), 2540 participants; low-certainty evidence) and the risk of all cardiovascular events (OR 0.86, 95% CI 0.77 to 0.96; 3 studies, 35,794 participants; low-certainty evidence). ASA increased the risk of major bleeding events (OR 1.77, 95% CI 1.34 to 2.32; 2 studies, 21,330 participants; high-certainty evidence). One study (CAPRIE; ASA versus clopidogrel) included patients diagnosed with hypertension (mean age 62.5 years, 72% males, 95% Caucasians, mean follow-up: 1.91 years). It showed no evidence of a difference for all-cause mortality (OR 1.02, 95% CI 0.91 to 1.15; 1 study, 19,143 participants; high-certainty evidence) and for cardiovascular mortality (OR 1.08, 95% CI 0.94 to 1.26; 1 study, 19,143 participants; high-certainty evidence). ASA probably reduced the risk of non-fatal cardiovascular events (OR 1.10, 95% CI 1.00 to 1.22; 1 study, 19,143 participants; high-certainty evidence) and the risk of all cardiovascular events (OR 1.08, 95% CI 1.00 to 1.17; 1 study, 19,143 participants; high-certainty evidence) when compared to clopidogrel. Clopidogrel increased the risk of major bleeding events when compared to ASA (OR 1.35, 95% CI 1.14 to 1.61; 1 study, 19,143 participants; high-certainty evidence). In one study (Huynh; ASA verus warfarin) patients with unstable angina or non-ST-segment elevation myocardial infarction, with prior coronary artery bypass grafting (CABG) were included (mean age 68 years, 79.8% males, mean follow-up: 1.1 year). There was no evidence of a difference for all-cause mortality (OR 0.98, 95% CI 0.06 to 16.12; 1 study, 91 participants; low-certainty evidence). Cardiovascular mortality, non-fatal cardiovascular events, and all cardiovascular events were not available. There was no evidence of a difference for major bleeding events (OR 0.13, 95% CI 0.01 to 2.60; 1 study, 91 participants; low-certainty evidence).  AUTHORS' CONCLUSIONS: There is no evidence that antiplatelet therapy modifies mortality in patients with elevated BP for primary prevention. ASA reduced the risk of cardiovascular events and increased the risk of major bleeding events.  Antiplatelet therapy with ASA probably reduces the risk of non-fatal and all cardiovascular events when compared to clopidogrel. Clopidogrel increases the risk of major bleeding events compared to ASA in patients with elevated BP for secondary prevention.  There is no evidence that warfarin modifies mortality in patients with elevated BP for secondary prevention.  The benefits and harms of the newer drugs glycoprotein IIb/IIIa inhibitors, clopidogrel, prasugrel, ticagrelor, and non-vitamin K antagonist oral anticoagulants for patients with high BP have not been studied in clinical trials. Further RCTs of antithrombotic therapy including newer agents and complete documentation of all benefits and harms are required in patients with elevated BP.

Resistant Hypertension: Detection, Evaluation, and Management: A Scientific Statement From the American Heart Association

Resistant hypertension (RH) is defined as above-goal elevated blood pressure (BP) in a patient despite the concurrent use of 3 antihypertensive drug classes, commonly including a long-acting calcium channel blocker, a blocker of the renin-angiotensin system (angiotensin-converting enzyme inhibitor or angiotensin receptor blocker), and a diuretic. The antihypertensive drugs should be administered at maximum or maximally tolerated daily doses. RH also includes patients whose BP achieves target values on ≥4 antihypertensive medications. The diagnosis of RH requires assurance of antihypertensive medication adherence and exclusion of the "white-coat effect" (office BP above goal but out-of-office BP at or below target). The importance of RH is underscored by the associated risk of adverse outcomes compared with non-RH. This article is an updated American Heart Association scientific statement on the detection, evaluation, and management of RH. Once antihypertensive medication adherence is confirmed and out-of-office BP recordings exclude a white-coat effect, evaluation includes identification of contributing lifestyle issues, detection of drugs interfering with antihypertensive medication effectiveness, screening for secondary hypertension, and assessment of target organ damage. Management of RH includes maximization of lifestyle interventions, use of long-acting thiazide-like diuretics (chlorthalidone or indapamide), addition of a mineralocorticoid receptor antagonist (spironolactone or eplerenone), and, if BP remains elevated, stepwise addition of antihypertensive drugs with complementary mechanisms of action to lower BP. If BP remains uncontrolled, referral to a hypertension specialist is advised.

Amlodipine and celecoxib for treatment of hypertension and osteoarthritis pain

INTRODUCTION

Osteoarthritis constitutes one of the leading causes of pain and disability worldwide with a significant impact on health-care costs. Patients with osteoarthritis are often affected by a number of cardiovascular comorbidities, including hypertension, which is present in about 40% of cases. Just recently, a single tablet combination of amlodipine besylate, a calcium channel blocker, and celecoxib, a nonsteroidal anti-inflammatory drug, indicated for patients for whom treatment with amlodipine for hypertension and celecoxib for osteoarthritis are appropriate, has been recently approved. Areas covered: We reviewed data from clinical studies that investigated safety and efficacy of the combination of amlodipine and celecoxib in hypertensive patients with osteoarthritis published before 31 August 2018. The literature search was conducted using research Methodology Filters. Expert commentary: The advantages of this single formulation over sequential administration include increased compliance, possibly reduced cost, and less likelihood of dosage-related issues. Moreover, this single tablet formulation combines the anti-inflammatory activity of the celecoxib with the systemic vasodilatation induced by the amlodipine. It is a promising treatment for patients with osteoarthritis and hypertension. Nevertheless, celecoxib may cause a variable degree of blood pressure increase and only a small clinical trial has been conducted before approval to assess interactions related to blood pressure effect between these two molecules.

Differential blood pressure effects of ibuprofen, naproxen, and celecoxib in patients with arthritis: the PRECISION-ABPM (Prospective Randomized Evaluation of Celecoxib Integrated Safety Versus Ibuprofen or Naproxen Ambulatory Blood Pressure Measurement) Trial

Aims

Non-steroidal anti-inflammatory drugs (NSAIDs), both non-selective and selective cyclooxygenase-2 (COX-2) inhibitors, are among the most widely prescribed drugs worldwide, but associate with increased blood pressure (BP) and adverse cardiovascular (CV) events. PRECISION-ABPM, a substudy of PRECISION was conducted at 60 sites, to determine BP effects of the selective COX-2 inhibitor celecoxib vs. the non-selective NSAIDs naproxen and ibuprofen.

Methods and results

In this double-blind, randomized, multicentre non-inferiority CV-safety trial, 444 patients (mean age 62 ± 10 years, 54% female) with osteoarthritis (92%) or rheumatoid arthritis (8%) and evidence of or at increased risk for coronary artery disease received celecoxib (100-200 mg bid), ibuprofen (600-800 mg tid), or naproxen (375-500 mg bid) with matching placebos in a 1: 1: 1 allocation, to assess the effect on 24-h ambulatory BP after 4 months. The change in mean 24-h systolic BP (SBP) in celecoxib, ibuprofen and naproxen-treated patients was -0.3 mmHg [95% confidence interval (CI), -2.25, 1.74], 3.7 (95% CI, 1.72, 5.58) and 1.6 mmHg (95% CI, -0.40, 3.57), respectively. These changes resulted in a difference of - 3.9 mmHg (P = 0.0009) between celecoxib and ibuprofen, of - 1.8 mmHg (P = 0.12) between celecoxib and naproxen, and of - 2.1 mmHg (P = 0.08) between naproxen and ibuprofen. The percentage of patients with normal baseline BP who developed hypertension (mean 24-h SBP ≥ 130 and/or diastolic BP ≥ 80 mmHg) was 23.2% for ibuprofen, 19.0% for naproxen, and 10.3% for celecoxib (odds ratio 0.39, P = 0.004 and odds ratio 0.49, P = 0.03 vs. ibuprofen and naproxen, respectively).

Conclusions

In PRECISION-ABPM, allocation to the non-selective NSAID ibuprofen, compared with the COX-2 selective inhibitor celecoxib was associated with a significant increase of SBP, and a higher incidence of new-onset hypertension.

ClinicalTrials

gov number NCT00346216.

Aspirin and blood pressure: Effects when used alone or in combination with antihypertensive drugs

Arterial hypertension is a major risk factor for cardiovascular and renal events. Lowering blood pressure is thus an important strategy for reducing morbidity and mortality. Since low-dose aspirin is a cornerstone in the prevention of adverse cardiovascular outcomes, combined treatment with aspirin and antihypertensive drugs is very common. However, the impact of aspirin therapy on blood pressure control remains a subject of intense debate. Recent data suggest that the cardioprotective action of aspirin extends beyond its well-known antithrombotic effect. Aspirin has been shown to trigger the synthesis of specialized pro-resolving lipid mediators from arachidonic acid and omega-3 fatty acids. These novel anti-inflammatory and pro-resolving mediators actively stimulate the resolution of inflammation and tissue regeneration. Additionally, they may contribute to other protective effects on redox status and vascular reactivity that have also been attributed to aspirin. Of note, aspirin has been shown to improve vasodilation through cyclooxygenase-independent mechanisms. On the other hand, higher aspirin doses have been reported to exert a negative impact on blood pressure due to inhibition of cyclooxygenase-2 activity, which reduces renal blood flow, glomerular filtration rate and sodium and water excretion. This review aims to provide an overview of the effects of aspirin on blood pressure and the underlying mechanisms, focusing on the interaction between aspirin and antihypertensive drugs. Studies in both experimental and human hypertension are presented.

Clinical Pharmacology and Cardiovascular Safety of Naproxen

The voluntary withdrawal of Vioxx (rofecoxib) from the market in 2004, as well as the 2005 and 2014 US FDA Advisory Committee meetings about non-steroidal anti-inflammatory drugs (NSAIDs) and cardiovascular risk, have raised questions surrounding the use of NSAIDs in at-risk populations. This paper discusses the cardiovascular safety profile of naproxen in the context of the NSAID class. The balance of evidence suggests that cardiovascular risk correlates with cyclooxygenase (COX)-2 selectivity, and the low COX-2 selectivity of naproxen results in a lower cardiovascular risk than that of other NSAIDs. The over-the-counter (OTC) use of naproxen is expected to pose minimal cardiovascular risk; however, the benefit-risk ratio and appropriate use should be considered at an individual patient level, particularly to assess underlying conditions that may increase the risk of events. Likewise, regulatory authorities should revisit label information periodically to ensure labeling reflects the current understanding of benefits and risks.

[Clinical relevance of drug interactions between nonsteroidal antiinflammatory drugs (NSAIDs) and antihypertensives]

Objetivo

Establecer la relevancia clínica de las interacciones medicamentosas reportadas entre antiinflamatorios no esteroideos (AINE) y antihipertensivos basándose en la gravedad y la probabilidad de ocurrencia de la interacción.

Diseño

Revisión sistemática.

Fuentes de datos

Se realizó una búsqueda en PubMed/Medline utilizando los términos Mesh: NSAIDs, Antihypertensive drugs y Drug interactions.

Extracción de datos

Se incluyeron publicaciones entre 2002 y 2012 de estudios en humanos, en español e inglés y con acceso a texto completo. Fueron incluidos los artículos que la búsqueda arrojó y algunas de las referencias usadas en dichos trabajos. Fueron excluidos los trabajos con métodos in vitro, con efectos sobre la hipertensión ocular y aquellos que no consideraran la interacción AINE-antihipertensivos. Para la selección de los trabajos incluidos participaron 3 revisores independientes. Se usó una herramienta especialmente diseñada para la extracción de datos y análisis de la relevancia clínica de la interacción.

Resultados

Se incluyeron 19 artículos de los 50 encontrados. Allí se identificaron 21 interacciones de mecanismo farmacodinámico, clasificadas por su relevancia clínica en nivel 2 (riesgo alto; 76,2%) y nivel 3 (riesgo medio; 23,8%). Adicionalmente se encontró evidencia de 16 combinaciones que no presentaron interacción.

Conclusiones

Algunos AINE pueden disminuir la efectividad del tratamiento antihipertensivo cuando se utilizan simultáneamente con antihipertensivos, en especial con inhibidores de la enzima conversora de angiotensina, diuréticos, bloqueadores beta y antagonistas de los receptores de angiotensina. No se encontró evidencia de la modificación del efecto de los antagonistas de los canales de calcio, especialmente dihidropiridínicos, por el uso simultáneo con AINE.

Comparative effects of non-steroidal anti-inflammatory drugs (NSAIDs) on blood pressure in patients with hypertension

Background

Nonsteroidal anti-inflammatory drugs (NSAIDs) may disrupt control of blood pressure in hypertensive patients and increase their risk of morbidity, mortality, and the costs of care. The objective of this study was to examine the association between incident use of NSAIDs and blood pressure in patients with hypertension.

Methods

We conducted a retrospective cohort study of adult hypertensive patients to determine the effects of their first prescription for NSAID on systolic blood pressure and antihypertensive drug intensification. Data were collected from an electronic medical record serving an academic general medicine practice in Indianapolis, Indiana, USA. Using propensity scores to minimize bias, we matched a cohort of 1,340 users of NSAIDs with 1,340 users of acetaminophen. Propensity score models included covariates likely to affect blood pressure or the use of NSAIDs. The study outcomes were the mean systolic blood pressure measurement after starting NSAIDs and changes in antihypertensive therapy.

Results

Compared to patients using acetaminophen, NSAID users had a 2 mmHg increase in systolic blood pressure (95% CI, 0.7 to 3.3). Ibuprofen was associated with a 3 mmHg increase in systolic blood pressure compared to naproxen (95% CI, 0.5 to 4.6), and a 5 mmHg increase compared to celecoxib (95% CI, 0.4 to 10). The systolic blood pressure increase was 3 mmHg in a subgroup of patients concomitantly prescribed angiotensin converting enzyme inhibitors or calcium channel blockers and 6 mmHg among those prescribed a beta-adrenergic blocker. Blood pressure changes in patients prescribed diuretics or multiple antihypertensives were not statistically significant.

Conclusion

Compared to acetaminophen, incident use of NSAIDs, particularly ibuprofen, is associated with a small increase in systolic blood pressure in hypertensive patients. Effects in patients prescribed diuretics or multiple antihypertensives are negligible.

Antiplatelet agents and anticoagulants for hypertension

BACKGROUND

Elevated systemic blood pressure results in high intravascular pressure but the main complications, coronary heart disease (CHD), ischaemic strokes and peripheral vascular disease (PVD), are related to thrombosis rather than haemorrhage. Some complications related to elevated blood pressure, heart failure or atrial fibrillation, are themselves associated with stroke and thromboembolism. Therefore it is important to investigate if antithrombotic therapy may be useful in preventing thrombosis-related complications in patients with elevated blood pressure.

OBJECTIVES

To conduct a systematic review of the role of antiplatelet therapy and anticoagulation in patients with high blood pressure, including those with elevations in both systolic and diastolic blood pressure, isolated elevations of either systolic or diastolic blood pressure, to address the following hypotheses: (i) antiplatelet agents reduce total deaths and/or major thrombotic events when compared to placebo or other active treatment; and (ii) oral anticoagulants reduce total deaths and/or major thromboembolic events when compared to placebo or other active treatment.

SEARCH METHODS

Electronic databases (MEDLINE, EMBASE, DARE, CENTRAL, Hypertension Group specialised register) were searched up to January 2011. The reference lists of papers resulting from the electronic searches and abstracts from national and international cardiovascular meetings were hand-searched to identify missed or unpublished studies. Relevant authors of studies were contacted to obtain further data.

SELECTION CRITERIA

Randomised controlled trials (RCTs) in patients with elevated blood pressure were included if they were of at least 3 months in duration and compared antithrombotic therapy with control or other active treatment.

DATA COLLECTION AND ANALYSIS

Data were independently collected and verified by two reviewers. Data from different trials were pooled where appropriate.

MAIN RESULTS

Four trials with a combined total of 44,012 patients met the inclusion criteria and are included in this review. Acetylsalicylic acid (ASA) did not reduce stroke or 'all cardiovascular events' compared to placebo in primary prevention patients with elevated blood pressure and no prior cardiovascular disease. In one large trial ASA taken for 5 years reduced myocardial infarction (ARR 0.5%, NNT 200), increased major haemorrhage (ARI 0.7%, NNT 154), and did not reduce all cause mortality or cardiovascular mortality. In one trial there was no significant difference between ASA and clopidogrel for the composite endpoint of stroke, myocardial infarction or vascular death. In two small trials warfarin alone or in combination with ASA did not reduce stroke or coronary events. The ATC meta-analysis of antiplatelet therapy for secondary prevention in patients with elevated blood pressure reported an absolute reduction in vascular events of 4.1% as compared to placebo. Data on the 10,600 patients with elevated blood pressure from the 29 individual trials included in the ATC meta-analysis was requested but could not be obtained.

AUTHORS' CONCLUSIONS

Antiplatelet therapy with ASA for primary prevention in patients with elevated blood pressure provides a benefit, reduction in myocardial infarction, which is negated by a harm of similar magnitude, increase in major haemorrhage.The benefit of antiplatelet therapy for secondary prevention in patients with elevated blood pressure is many times greater than the harm.Benefit has not been demonstrated for warfarin therapy alone or in combination with aspirin in patients with elevated blood pressure. Ticlopidine, clopidogrel and newer antiplatelet agents such as prasugrel and ticagrelor have not been sufficiently evaluated in patients with high blood pressure. Newer antithrombotic oral drugs such as dabigatran, rivaroxaban, apixaban and endosaban are yet to be tested in patients with high blood pressure.Further trials of antithrombotic therapy including with newer agents and complete documentation of all benefits and harms are required in patients with elevated blood pressure.

Low-dose acetylsalicylic acid and blood pressure control in drug-treated hypertensive patients

BACKGROUND

Nonsteroidal anti-inflammatory drugs (NSAIDs) may increase blood pressure (BP) and potentially reduce the efficacy of several antihypertensive drugs. We evaluated the effect of low-dose acetylsalicylic acid (ASA) on BP control in drug-treated hypertensive patients in a primary care population.

DESIGN/METHODS

Nine hundred and five successive patients aged 25–91 years (mean 65.5 years) from 15 health centers in south-west Finland were studied. The patients were on antihypertensive monotherapy (45.7%) or on combination therapy (54.3%). Office BP was measured twice with a 2-min interval after at least a 10-min rest using an ordinary sphygmomanometer.

RESULTS

Patients receiving ASA (n = 246) showed lower diastolic BP (83.9 ± 9.0 vs. 87.0 ± 9.6 mmHg; P < 0.001) compared with those who were not using any NSAIDs (n = 659). No significant difference in systolic BP was observed between the groups. As a result, pulse pressure was slightly higher in the ASA group (66.9 ± 18.9 vs. 63.3 ± 17.7 mmHg, P = 0.01). Mean arterial pressure was lower in the ASA group (106.2 ± 10.6 vs. 108.1 ± 10.4 mmHg, P = 0.02). In a stepwise linear multivariate model, ASA remained a significant predictor of lower diastolic BP even after the adjustment with the confounding effects of age and sex.

CONCLUSION

According to our population-based study low-dose ASA does not have deleterious effects on BP control in drug-treated hypertensive patients.

Is there a BP benefit of changing the time of aspirin administration in treated hypertensive patients?

Background and design: The effects of aspirin on blood pressure (BP) are controversial and a chronopharmacological effect of aspirin on 24-hour BP was reported recently in otherwise untreated hypertensive patients. The study was designed to test the timing effect of aspirin dosing on 24-hour BP in treated hypertensive patients routinely taking aspirin for cardiovascular prevention.

Method and results: Seventy-five patients were randomized into two groups. One group was to receive aspirin in the evening then in the morning for 1 month and the other group in the morning then in the evening, following a cross-over design. The principal assessment criterion was 24-hour systolic BP (SBP) measured by 24-hour ambulatory BP monitoring (ABPM). Patients were aged 65 ± 9 years and had been hypertensive for 12 ± 10 years. They were all taking a mean of 2.8 antihypertensive drugs and did not modify their treatment throughout the study. Of the included subjects, 70% were men and 33% were diabetics. Mean 24-hour SBP values were clinically equivalent and were not statistically different, depending on whether the aspirin was taking in the morning or evening (128.3 ± 1.4 vs. 128.3 ± 1.4 mmHg, respectively). Neither was there any significant difference in diurnal and nocturnal SBP or in 24-hour, diurnal, and nocturnal diastolic BP (DBP).

Conclusion: It does not appear useful to advise patients with long-standing hypertension to modify timing of aspirin intake in order to reduce BP values.

Antihypertensive effects of aspirin: what is the evidence?

Nonsteroidal anti-inflammatory drugs are known to increase blood pressure and blunt the effect of antihypertensive drugs. Surprisingly, it has been suggested recently that aspirin lowers blood pressure and could be used for preventing hypertension. This review summarizes published data on the effects of aspirin on blood pressure. Trials suggesting that aspirin administered at bedtime lowers blood pressure are uncontrolled, unmasked, and potentially biased. They also conflict with cohort studies showing an 18% increase in the risk of hypertension among aspirin users. Fortunately, short-term use of aspirin does not seem to interfere with antihypertensive drugs. Regardless of its effect on blood pressure, low-dose aspirin effectively prevents cardiovascular events in patients with and without hypertension, but its benefits should be carefully weighed against a potential increase in the risk of adverse effects such as gastric bleeding and hemorrhagic stroke, as well as a small increase in the risk of hypertension.

Treatment strategies for osteoarthritis patients with pain and hypertension

Out of 100 patients with osteoarthritis (OA), almost 40 have a concomitant diagnosis of hypertension. Nonsteroidal anti-inflammatory drugs (NSAIDs) and cyclooxygenase-2 (COX-2) inhibitors may trigger a rise in blood pressure (BP), which is more marked in patients with established hypertension. NSAIDs and COX-2 inhibitors attenuate the antihypertensive effect of several antihypertensive agents. Frequent BP controls are needed in treated hypertensive patients who are concomitantly receiving NSAIDs or COX-2 inhibitors because even a small increase in BP may be associated with an important rise in the risk of major cardiovascular complications. In meta-analyses, an increase in systolic BP of 5mmHg was associated with a 25% higher risk of cardiovascular events. These data have been confirmed in randomized studies with rofecoxib and celecoxib, where a modest increase in BP was associated with a significantly higher risk of cardiovascular disease. There is emerging evidence that the COX-inhibiting nitric oxide donator (CINOD) class is promising in the treatment of patients with OA. Naproxcinod, the first CINOD investigated in clinical trials, is composed of the traditional NSAID naproxen covalently bound to the nitric oxide (NO)-donating moiety butanediol mono-nitrate (BDMN). The molecule has the potential to provide a sustained release of NO. In clinical studies, naproxcinod prevented the BP rise in normotensive and hypertensive patients observed with naproxen. The BP benefit of naproxcinod over naproxen was greater in patients concomitantly receiving angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers. These investigational data suggest that naproxcinod is a valuable alternative to NSAIDs and COX-2 inhibitors for treatment of OA patients.

Aspirin, non-aspirin analgesics and the risk of hypertension in the SUN cohort

INTRODUCTION AND OBJECTIVES

The use of aspirin and non-aspirin analgesics has been associated with changes in blood pressure. The aim of this study was to investigate prospectively the association between the regular use of aspirin and non-aspirin analgesics and the incidence of hypertension.

METHODS

The SUN project is an ongoing, continuously expanding, prospective cohort of Spanish university graduates initially free of hypertension, cardiovascular disease, diabetes and cancer; 9986 (mean age 36 years) were recruited during 1999-2005 and followed up for a mean of 51 months. Regular aspirin and non-aspirin analgesic use and the presence of other risk factors for hypertension were assessed by questionnaire at baseline, and the incidence of hypertension was assessed using biennial follow-up questionnaires.

RESULTS

In total, 543 new cases of hypertension were identified during follow-up. Regular aspirin use (i.e. 2 or more days/week) was associated with a higher risk of hypertension (hazard ratio=1.45; 95% confidence interval, 1.02-2.04) after adjustment for various confounding factors. Regular use of non-aspirin analgesic drugs was also associated with a higher risk of hypertension (hazard ratio=1.69; 95% confidence interval, 1.28-2.23).

CONCLUSIONS

The regular use of aspirin and non-aspirin analgesics were both associated with an increased risk of developing hypertension, independently of other risk factors.

The effect of non-steroidal anti-inflammatory drugs and other commonly used non-narcotic analgesics on blood pressure level in adults

This review explores the blood pressure effects of three non-narcotic analgesics: non-selective non-steroidal anti-inflammatory drugs (NSAID), paracetamol and aspirin. The current evidence suggests that in normotensive, otherwise healthy adults, short-term use (1-2 weeks) of NSAIDs is not associated with a significant increase in blood pressure. Those with existing hypertension are more likely to see a blood pressure elevation, although the magnitude of the effect is less predictable and may vary with age, baseline blood pressure, type of NSAID and concurrent antihypertensive therapy. The magnitude of the blood pressure increase appears to be similar for both NSAIDs and paracetamol, while low-dose aspirin may have more modest effects. In hypertensive adults who experience deterioration of blood pressure control on NSAIDs, there is some, albeit suboptimal, evidence that the blood pressure-raising effects of NSAIDs are less when used in conjunction with dihydropyridine calcium-channel blockers than angiotensin-converting enzyme inhibitors.

Antithrombotic therapy in hypertension: a Cochrane Systematic review

Although elevated systemic blood pressure (BP) results in high intravascular pressure, the main complications of hypertension are related to thrombosis rather than haemorrhage. It therefore seemed plausible that use of antithrombotic therapy may be useful in preventing thrombosis-related complications of elevated BP. The objectives were to conduct a systematic review of the role of antiplatelet therapy and anticoagulation in patients with BP, to address the following hypotheses: (i) antiplatelet agents reduce total deaths and/or major thrombotic events when compared to placebo or other active treatment; and (ii) oral anticoagulants reduce total deaths and/or major thromboembolic events when compared to placebo or other active treatment. A systematic review of randomised studies in patients with elevated BP was performed. Studies were included if they were >3 months in duration and compared antithrombotic therapy with control or other active treatment. One meta-analysis of antiplatelet therapy for secondary prevention in patients with elevated BP reported an absolute reduction in vascular events of 4.1% as compared to placebo. Acetylsalicylic acid (ASA) did not reduce stroke or 'all cardiovascular events' compared to placebo in primary prevention patients with elevated BP and no prior cardiovascular disease. Based on one large trial, ASA taken for 5 years reduced myocardial infarction (ARR, 0.5%, NNT 200 for 5 years), increased major haemorrhage (ARI, 0.7%, NNT 154), and did not reduce all cause mortality or cardiovascular mortality. In two small trials, warfarin alone or in combination with ASA did not reduce stroke or coronary events. Glycoprotein IIb/IIIa inhibitors as well as ticlopidine and clopidogrel have not been sufficiently evaluated in patients with elevated BP. To conclude for primary prevention in patients with elevated BP, antiplatelet therapy with ASA cannot be recommended since the magnitude of benefit, a reduction in myocardial infarction, is negated by a harm of similar magnitude, an increase in major haemorrhage. For secondary prevention in patients with elevated BP, antiplatelet therapy is recommended because the magnitude of the absolute benefit is many times greater. Warfarin therapy alone or in combination with aspirin in patients with elevated BP cannot be recommended because of lack of demonstrated benefit. Further trials of antithrombotic therapy are required in patients with elevated BP.

Antiplatelet agents and anticoagulants for hypertension

BACKGROUND

Although elevated systemic blood pressure results in high intravascular pressure, the main complications, coronary heart disease (CHD), ischaemic strokes and peripheral vascular disease (PVD), are related to thrombosis rather than haemorrhage. Some complications related to elevated blood pressure, heart failure or atrial fibrillation, are themselves associated with stroke and thromboembolism. It therefore seemed plausible that use of antithrombotic therapy may be particularly useful in preventing thrombosis-related complications of elevated blood pressure.

OBJECTIVES

To conduct a systematic review of the role of antiplatelet therapy and anticoagulation in patients with blood pressure, including those with elevations in both systolic and diastolic blood pressure, isolated elevations of either systolic or diastolic blood pressure, to address the following hypotheses: (i) antiplatelet agents reduce total deaths and/or major thrombotic events when compared to placebo or other active treatment; and (ii) oral anticoagulants reduce total deaths and/or major thromboembolic events when compared to placebo or other active treatment.

SEARCH STRATEGY

Reference lists of papers resulting from this search, electronic database searching (MEDLINE, EMBASE, DARE), and abstracts from national and international cardiovascular meetings were studied to identify unpublished studies. Relevant authors of these studies were contacted to obtain further data.

SELECTION CRITERIA

Randomised controlled trials (RCTs) in patients with elevated blood pressure were included if they were of at least 3 months in duration and compared antithrombotic therapy with control or other active treatment.

DATA COLLECTION AND ANALYSIS

Data were independently collected and verified by two reviewers. Data from different trials were pooled where appropriate.

MAIN RESULTS

The ATC meta-analysis of antiplatelet therapy for secondary prevention in patients with elevated blood pressure reported an absolute reduction in vascular events of 4.1% as compared to placebo. Data on the patients with elevated blood pressure from the 29 individual trials included in this meta-analysis was requested but could not be obtained. Three additional trials met the inclusion criteria and are reported on here. Acetylsalicylic acid (ASA) did not reduce stroke or 'all cardiovascular events' compared to placebo in primary prevention patients with elevated blood pressure and no prior cardiovascular disease. Based on one large trial (HOT trial), ASA taken for 5 years reduced myocardial infarction (ARR, 0.5%, NNT 200 for 5 years), increased major haemorrhage (ARI, 0.7%, NNT 154), and did not reduce all cause mortality or cardiovascular mortality. There was no significant difference between ASA and clopidogrel for the composite endpoint of stroke, myocardial infarction or vascular death in one trial (CAPRIE 1996). In two small trials warfarin alone or in combination with ASA did not reduce stroke or coronary events.

REVIEWERS' CONCLUSIONS

For primary prevention in patients with elevated blood pressure, anti-platelet therapy with ASA cannot be recommended since the magnitude of benefit, a reduction in myocardial infarction, is negated by a harm of similar magnitude, an increase in major haemorrhage. For secondary prevention in patients with elevated blood pressure (ATC meta-analysis: APTC 1994) antiplatelet therapy is recommended because the magnitude of the absolute benefit is many times greater. Warfarin therapy alone or in combination with aspirin in patients with elevated blood pressure cannot be recommended because of lack of demonstrated benefit. Glycoprotein IIb/IIIa inhibitors as well as ticlopidine and clopidogrel have not been sufficiently evaluated in patients with elevated blood pressure. Further trials of antithrombotic therapy with complete documentation of all benefits and harms are required in patients with elevated blood pressure.

Coxibs--beyond the GI tract: renal and cardiovascular issues

Although the coxibs have demonstrated superior gastrointestinal safety compared to traditional non-selective NSAIDs, questions remain regarding their effects on the renal and cardiovascular systems. In terms of renal function, both Type 1 and Type 2 cyclooxygenase (COX-1 and COX-2) are expressed constitutively in the kidney. Prostaglandins do not play a major role in the maintenance of renal function in healthy individuals but they become profoundly important in certain clinical situations such as renal stress, or volume depletion. In such situations the effects of the coxibs and non-selective NSAIDs are likely to be similar. The incidence of renal side effects is low (1-5%) and the patients at risk of renal complications are well defined and can usually be identified prospectively and followed up as appropriate. From the cardiovascular point of view, questions have been raised as to whether the coxibs have a prothrombotic effect. Here we review the available evidence and consider various hypotheses for an apparent increase in cardiovascular events reported in one coxib study (the VIGOR trial). Because of a lack of anti-platelet activity, coxibs are not suited for the provision of cardiovascular prophylaxis, and in patients at risk of myocardial infarction the prophylactic use of aspirin should always be considered. Although evidence suggests that use of coxibs with low-dose aspirin is safer than the combination of traditional NSAIDs with aspirin, further studies are required to confirm that this is the case.

Effects of celecoxib and rofecoxib on blood pressure and edema in patients > or =65 years of age with systemic hypertension and osteoarthritis

Concomitant use of nonsteroidal anti-inflammatory drugs (NSAIDs), including the cyclooxygenase-2 (COX-2) specific inhibitors, with antihypertensive medication is common practice for many patients with arthritis. This study evaluated the effects of celecoxib 200 mg/day and rofecoxib 25 mg/day on blood pressure (BP) and edema in a 6-week, randomized, parallel-group, double-blind study in patients > or =65 years of age with osteoarthritis who were treated with fixed antihypertensive regimens. One thousand ninety-two patients received study medication (celecoxib, n = 549; rofecoxib, n = 543). Significantly more patients in the rofecoxib group compared with the celecoxib group developed increased systolic BP (change >20 mm Hg plus absolute value > or =140 mm Hg) at any time point (14.9% vs 6.9%, p <0.01). Rofecoxib caused the greatest increase in systolic BP in patients receiving angiotensin-converting enzyme inhibitors or beta blockers, whereas those on calcium channel antagonists or diuretic monotherapy receiving either celecoxib or rofecoxib showed no significant increases in BP. Clinically significant new-onset or worsening edema associated with weight gain developed in a greater percentage of patients in the rofecoxib group (7.7%) compared with the celecoxib group (4.7%) (p <0.05). Thus, in patients with controlled hypertension on a fixed antihypertensive regimen, careful monitoring of BP is warranted after the initiation of celecoxib or rofecoxib therapy.

Effect of indomethacin on the antihypertensive efficacy of valsartan and lisinopril: a multicentre study

OBJECTIVE

To compare the effect on antihypertensive efficacy produced by the addition of indomethacin to the angiotensin II (Ang II) antagonist, valsartan, or to the angiotensin-converting enzyme inhibitor, lisinopril, in hypertensive patients with chronic osteoarthritis.

SUBJECTS AND METHODS

One hundred and twenty-eight patients (52 men and 76 women) aged 25-82 years (mean age 55.7 years), with diastolic blood pressure (DBP) > 100 mmHg at the end of a 2-week placebo washout period were allocated randomly to groups to receive valsartan (80-160 mg once daily) or lisinopril (10-20 mg once daily). At the end of 10 weeks of treatment, patients with DBP < 90 mmHg, while continuing to receive valsartan or lisinopril treatment, were allocated randomly to groups to receive either indomethacin (50 mg three times a day) or the corresponding placebo for 2 weeks, with a 1-week washout period between the two treatments, according to a double-blind, crossover design. After the initial washout period, patients were examined at the end of the 4th, 8th and 10th weeks of randomized treatment with valsartan and lisinopril, at the end of the first crossover period and then at the beginning and at the end of the second crossover period. At each visit, sitting and standing blood pressure were measured by standard mercury sphygmomanometer.

RESULTS

The addition of indomethacin blunted the blood pressure-decreasing effect of both antihypertensive drugs. Although indomethacin produced greater increases in both systolic and DBP values in the lisinopril-treated patients (5.45/3.22 mmHg) than in the valsartan-treated ones (2.12/1.87 mmHg), no significant difference between the two drugs was found.

CONCLUSIONS

From a theoretical standpoint, these findings suggest that prostaglandins may play a part in the antihypertensive action of Ang II antagonists. From a practical standpoint, hypertensive patients treated with valsartan or with lisinopril should be monitored to detect changes in blood pressure control while receiving indomethacin.

Interaction between Aspirin and ACE Inhibitors in Patients with Heart Failure

Both aspirin (acetylsalicylic acid) and ACE inhibitors are often used concomitantly, especially in patients with both heart failure and ischaemic heart disease, which is the most common underlying cause of heart failure. The safety of the association has been questioned because both drugs affect a related prostaglandin-mediated pathway. Thanks to their vasodilating properties, prostaglandins play an important role in heart failure where peripheral vasoconstriction occurs. Some of the beneficial effects of ACE inhibitors might be related to reduced degradation of bradykinin that enhances the synthesis of prostaglandins, while aspirin, through inhibiting the enzyme cyclo-oxygenase, inhibits the production of prostaglandins. To date no prospective study has been conducted to investigate the effect of long term aspirin treatment in the postinfarction period allowing the possible impact of the interaction between aspirin and ACE inhibitors upon survival to be confirmed or negated. However, the practitioner needs to know how to optimise the treatment of his or her patients. In order to stimulate arguments for and against the use of aspirin in patients with heart failure receiving ACE inhibitors, we searched MEDLINE from 1960 to 2000 using the key words heart failure, aspirin, and ACE inhibitors for English language articles and conducted a review of the available data. We report on the potential mechanisms of the interaction and the results of experimental studies on haemodynamic parameters. Results of retrospective clinical studies, subgroup analysis that were undertaken to evaluate the overall action upon haemodynamic parameters and survival of the association are summarised. Conflicting conclusions have been reported in the literature. Many explanations can be advanced to try to understand these conflicting conclusions: differences in study design (results of retrospective trials have to be interpreted with caution); differences in the choice of the evaluation parameter (problem of the clinical relevance of haemodynamic parameters); differences in the characteristics of the patient (different underlying cardiopathy, e.g. heart failure, hypertension or ischaemic cardiopathy); and differences in the type and the dosage of each treatment (especially ACE inhibitors and aspirin since an interaction might occur more often with dosage of aspirin greater than 250mg).

Effect of indomethacin on blood pressure in elderly people with essential hypertension well controlled on amlodipine or enalapril

Arthritis and hypertension are frequent comorbidities in the elderly hypertensive population. Nonsteroidal anti-inflammatory drugs are often used to relieve pain in arthritic patients but a side effect is sodium retention and consequent elevation of blood pressure (BP). The effect of dihydropyridine calcium blocking drugs is relatively independent of sodium intake, whereas the angiotensin-converting enzyme (ACE) inhibitors' effects can be blunted by a high-sodium diet. This study compared the effects of indomethacin with placebo in elderly patients with essential hypertension who had been controlled with amlodipine or enalapril. Indomethacin 50 mg twice daily or placebo was administered for 3 weeks in a double-blind crossover study to patients controlled with amlodipine or enalapril. The response was assessed by ambulatory BP measurement. Indomethacin raised BP and lowered pulse rates in patients taking enalapril but had little effect in patients receiving amlodipine. The difference caused by indomethacin between the two groups was 10.1/4.9 mm Hg increase in BP and a 5.6 beats/min fall in pulse in people taking enalapril. Addition of indomethacin to patients taking either drug caused a rise in weight and a fall in plasma renin. It is postulated that the effect is due to inhibition of prostaglandin synthesis, which causes sodium retention. In patients taking amlodipine, the fall in plasma renin ameliorates the effect of sodium retention on BP. In patients taking enalapril, plasma renin falls but this is not translated into an effect because of the blockage of converting enzyme. Thus, the full effect of sodium retention on BP is expressed. In patients treated with indomethacin, fewer patients may respond to ACE inhibitors. However, the major problem is the patient who intermittently takes indomethacin or other nonsteroidal anti-inflammatory drugs, which, if a person is treated by an ACE inhibitor causes BP to go out of control. In such patients amlodipine would appear to be a preferred choice to enalapril.

Update on the interaction between aspirin and angiotensin-converting enzyme inhibitors

We summarized recent published literature regarding the significance of an interaction between aspirin and angiotensin-converting enzyme (ACE) inhibitors in patients with various cardiovascular diseases. A MEDLINE search (January 1998-July 1999) was performed and abstracts from the 1999 American College of Cardiology and 1998 American Heart Association annual scientific sessions were reviewed to identify pertinent studies. Material for discussion was identified through a MEDLINE search from January 1996-July 1999 and through cited references. The results of several studies added to our understanding of the clinical ramifications of an aspirin-ACE inhibitor interaction, but also introduced questions. These studies are largely contradictory, but do reiterate the possibility of an interaction, if only in certain subsets of patients. Low dosages (< or = 100 mg/day) of aspirin appear to be safer in this regard than higher dosages. The frequency and severity of the interaction and possible predisposing factors await future research.

Effects of low-dose aspirin on clinic and ambulatory blood pressure in treated hypertensive patients. Collaborative Group of the Primary Prevention Project (PPP)--Hypertension study

Nonsteroidal antiinflammatory drugs may affect blood pressure (BP) control in hypertensive patients receiving drug treatment, but data on the effects of low-dose aspirin are scanty. This study assessed the effects of chronic treatment with low doses of aspirin (100 mg/day) on clinic and ambulatory systolic (SBP) and diastolic (DBP) BP in hypertensives on chronic, stable antihypertensive therapy. The study was conducted in the framework of the Primary Prevention Project (PPP), a randomized, controlled factorial trial on the preventive effect of aspirin or vitamin E in people with one or more cardiovascular risk factors. Fifteen Italian hypertension units studied 142 hypertensive patients (76 men, 66 women; mean age 59 +/- 5.9 years) treated with different antihypertensive drugs: 71 patients were randomized to aspirin and 71 served as controls. All patients underwent a clinic BP evaluation with an automatic sphygmomanometer and a 24-h ambulatory BP monitoring, at baseline and after 3 months of aspirin treatment. At the end of the study the changes in clinic SBP and DBP were not statistically different in treated and untreated subjects. Ambulatory SBP and DBP after 3 months of aspirin treatment were similar to baseline: deltaSBP -0.5 mmHg (95% confidence intervals [CI] from -1.9 to +2.9 mm Hg) and deltaDBP -1.1 mm Hg (95% CI from -2.5 to +0.3 mm Hg). The pattern was similar in the control group. No interaction was found between aspirin and the most used antihypertensive drug classes (angiotensin converting enzyme inhibitors and calcium antagonists). Despite the relatively small sample size our results seem to exclude any significant influence of low-dose aspirin on BP control in hypertensives under treatment.

Effect of indomethacin on the renal response to angiotensin II receptor blockade in healthy subjects

BACKGROUND

Non-steroidal anti-inflammatory drugs are known to promote sodium retention and to blunt the blood pressure lowering effects of several classes of antihypertensive agents including beta-blockers, diuretics and angiotensin converting enzyme (ACE) inhibitors. The purpose of the present study was to investigate the acute and sustained effects of indomethacin on the renal response to the angiotensin II receptor antagonist valsartan and to the ACE inhibitor enalapril.

METHODS

Twenty normotensive subjects maintained on fixed sodium intake (100 mmol sodium/day) were randomized to receive for one week: valsartan 80 mg o.d., enalapril 20 mg o.d., valsartan 80 mg o.d. + indomethacin 50 mg bid and enalapril 20 mg o.d. + indomethacin 50 mg bid. This single-blind study was designed as a parallel (valsartan vs. enalapril) and cross-over trial (valsartan or enalapril vs. valsartan + indomethacin or enalapril + indomethacin). Renal hemodynamics and urinary electrolyte excretion were measured for six hours after the first and seventh administration of each treatment regimen.

RESULTS

The results show that valsartan and enalapril have comparable renal effects characterized by no change in glomerular filtration rate and significant increases in renal plasma flow and sodium excretion. The valsartan- and enalapril-induced renal vasodilation is not significantly blunted by indomethacin. However, indomethacin similarly abolishes the natriuresis induced by the angiotensin II antagonist and the ACE inhibitor.

CONCLUSIONS

This observation suggests that although angiotensin receptor antagonists do not affect prostaglandin metabolism, the administration of a non-steroidal anti-inflammatory drug blunts the natriuretic response to angiotensin receptor blockade.

Arterial function in mineralocorticoid-NaCl hypertension: influence of angiotensin-converting enzyme inhibition

Angiotensin-converting enzyme inhibitors have been suggested to improve the function of arterial endothelium and smooth muscle not only through inhibition of angiotensin II formation and reduction of blood pressure, but also via additional pathways, e.g. potentiation of endogenous kinins and enhancement of endothelial autacoid formation. Therefore, we investigated whether 10-week-long quinapril therapy (10 mg kg-1 day-1) could beneficially influence the function of mesenteric arterial rings in vitro in deoxycorticosterone-NaCl-treated Wistar-Kyoto rats, a model of hypertension which is known to be resistant to angiotensin-converting enzyme inhibition. The quinapril treatment had no long-term blood pressure-lowering effect nor did it reduce the associated cardiac hypertrophy in deoxycorticosterone-NaCl hypertension. In noradrenaline-precontracted arterial rings the endothelium-dependent relaxations to acetylcholine and adenosine 5'-diphosphate as well as the endothelium-independent relaxations to nitroprusside and isoprenaline were clearly attenuated in the deoxycorticosterone-NaCl-treated rats. However, the quinapril therapy was without significant effect on any of these dilatory responses. In the presence of the nitric oxide synthase inhibitor NG-nitro-L-arginine methyl ester, the relaxations to acetylcholine in untreated and quinapril-treated hypertensive animals were practically absent, whereas in normotensive rats distinct relaxations to higher concentrations of acetylcholine were still present. Interestingly, when endothelium-dependent hyperpolarization was prevented by precontracting the preparations with potassium chloride, no differences were found in relaxations to acetylcholine and adenosine 5'-diphosphate between the study groups. Exogenous bradykinin induced small comparable contractions in endothelium-intact mesenteric arterial rings from all study groups. In conclusion, the 10-week-long quinapril therapy did not have any significant effects on arterial function in deoxycorticosterone-NaCl hypertensive rats. Therefore, the present results stress the roles of reduced blood pressure and diminished angiotensin II formation in the beneficial vascular effects of long-term angiotensin-converting enzyme inhibition in the present model of hypertension. Furthermore, since the relaxations to acetylcholine and adenosine 5'-diphosphate in the deoxycorticosterone-NaCl-treated rats were attenuated in the absence and presence of nitric oxide synthase inhibition but not under conditions which prevented hyperpolarization, impaired endothelium-dependent relaxation to agonists can be attributed to diminished endothelium-dependent hyperpolarization in this model of hypertension.