Differing administration time-dependent effects of aspirin on blood pressure in dipper and non-dipper hypertensives

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.

Circadian rhythms of risk factors and management in atherosclerotic and hypertensive vascular disease: Modern chronobiological perspectives of an ancient disease

Atherosclerosis, a chronic inflammatory disease of the arteries that appears to have been as prevalent in ancient as in modern civilizations, is predisposing to life-threatening and life-ending cardiac and vascular complications, such as myocardial and cerebral infarctions. The pathogenesis of atherosclerosis involves intima plaque buildup caused by vascular endothelial dysfunction, cholesterol deposition, smooth muscle proliferation, inflammatory cell infiltration and connective tissue accumulation. Hypertension is an independent and controllable risk factor for atherosclerotic cardiovascular disease (CVD). Conversely, atherosclerosis hardens the arterial wall and raises arterial blood pressure. Many CVD patients experience both atherosclerosis and hypertension and are prescribed medications to concurrently mitigate the two disease conditions. A substantial number of publications document that many pathophysiological changes caused by atherosclerosis and hypertension occur in a manner dependent upon circadian clocks or clock gene products. This article reviews progress in the research of circadian regulation of vascular cell function, inflammation, hemostasis and atherothrombosis. In particular, it delineates the relationship of circadian organization with signal transduction and activation of the renin-angiotensin-aldosterone system as well as disturbance of the sleep/wake circadian rhythm, as exemplified by shift work, metabolic syndromes and obstructive sleep apnea (OSA), as promoters and mechanisms of atherogenesis and risk for non-fatal and fatal CVD outcomes. This article additionally updates advances in the clinical management of key biological processes of atherosclerosis to optimally achieve suppression of atherogenesis through chronotherapeutic control of atherogenic/hypertensive pathological sequelae.

Circadian Blood Pressure Rhythm in Cardiovascular and Renal Health and Disease

Blood pressure (BP) follows a circadian rhythm, it increases on waking in the morning and decreases during sleeping at night. Disruption of the circadian BP rhythm has been reported to be associated with worsened cardiovascular and renal outcomes, however the underlying molecular mechanisms are still not clear. In this review, we briefly summarized the current understanding of the circadian BP regulation and provided therapeutic overview of the relationship between circadian BP rhythm and cardiovascular and renal health and disease.

Effects of low-molecular-weight heparin and aspirin in recurrent pre-eclampsia: A stratified cohort study

OBJECTIVE

To evaluate the effects of low-molecular-weight heparin (LMWH) combined with low-dose aspirin (LDA) in pregnant women with a history of pregnancy-related hypertensive disorders.

METHODS

In the current retrospective stratified cohort study, 33 women with previous hypertensive disorders of pregnancy treated with LMWH and LDA were compared with 37 control women who did not undergo LMWH or LDA treatment. Rates of pre-eclampsia recurrence, placental abruption, and other adverse outcomes for the fetuses and pregnant women were compared in the two groups.

RESULTS

The pre-eclampsia recurrence rates were 12/33 (36.4%) in the LMWH + LDA group and 28/37 (75.7%) in the control group (P < 0.01). In stratified cohort analysis, pregnant women with a history of early-onset pre-eclampsia, a body mass index of at least 24 (calculated as weight in kilograms divided by the square of height in meters), and aged less than 35 years benefited from LMWH + LDA treatment. In women with chronic hypertension or a history of placental abruption there was no protective effect. There were no significant differences in other adverse outcomes such as placental abruption and small size for gestational age in fetuses or pregnant women in the two groups.

CONCLUSION

Administration of LMWH + LDA only lowered the risk of pre-eclampsia recurrence in subgroups of pregnant women with a history of pregnancy-associated hypertensive disorders.

A Systematic Review of the Efficacy and Safety of Aspirin When Delivered at Different Medication Times for the Primary and Secondary Prevention of Cardiovascular and Cerebrovascular Diseases

PURPOSE

Effective antiplatelet therapy can significantly reduce the incidence and mortality rate of cardiovascular and cerebrovascular diseases. Aspirin is widely used in the secondary prevention of cardiovascular and cerebrovascular diseases; however, there is widespread debate as to when patients should take an enteric-coated aspirin tablet on a daily basis. In the present study, we evaluated the efficacy and safety of different aspirin medication times (morning or before bedtime) in terms of the primary and secondary prevention of cardiovascular and cerebrovascular diseases using meta-analysis.

METHODS

Studies with randomized control trials (RCT) or crossover trials regarding to the usage of aspirin (morning or before bedtime) for the primary or secondary prevention of cardiovascular and cerebrovascular diseases were searched in Medline, EMbase, Cochrane Library, CNKI, Wanfang Data, VIP Database and CBM. Review Manager 5 (RevMan 5, v5.3), a Cochrane systematic reviews software, was used to perform meta-analysis based on the recommendation of the Cochrane Handbook for risk assessment tools.

RESULTS

Meta-analysis showed that taking low-dose aspirin tablets before bed reduced systolic and diastolic blood pressure compared with taking it in the morning. At the same time, the number of studies on platelet aggregation rate, C-reactive protein (CRP), serum nitric oxide (NO) or thromboxane B₂ (TXB₂) is too small to be reliable. However, there was a large heterogeneity across the studies. The quality of some studies was not high enough.

CONCLUSION

Additional blood pressure benefits can be achieved by taking aspirin before bedtime, but it does not affect its antiplatelet effect and does not pose a higher risk of bleeding.

ADIPS 2020 guideline for pre-existing diabetes and pregnancy

This is the full version of the Australasian Diabetes in Pregnancy Society (ADIPS) 2020 guideline for pre-existing diabetes and pregnancy. The guideline encompasses the management of women with pre-existing type 1 diabetes and type 2 diabetes in relation to pregnancy, including preconception, antepartum, intrapartum and postpartum care. The management of women with monogenic diabetes or cystic fibrosis-related diabetes in relation to pregnancy is also discussed.

The impact of acetylsalicylic acid dosed at bedtime on circadian rhythms of blood pressure in the high-risk group of cardiovascular patients-a randomized, controlled trial

Purpose

Time of drug administration may significantly influence its effect. The aim of the present study was to investigate the effect of ASA (administrated in the morning or in the evening) on the anti-hypertensive effect and diurnal blood pressure profile in the high-risk group of cardiovascular patients.

Methods

All patients (n = 114) had been diagnosed with coronary heart disease and arterial hypertension prior to the enrolment and had been treated with 75 mg per day of ASA in the morning. The patients were randomly assigned to one of the two study groups receiving 75 mg of ASA per day in a single antiplatelet therapy for 3 months in the morning (n = 58) or in the evening (n = 56). The control group (n = 61) consisted of patients with arterial hypertension but without coronary heart disease, not receiving ASA. In all the patients, during each visit, clinical blood pressure (BP) and ambulatory blood pressure measurements (ABPM) were performed.

Results

There was a significant reduction in 24-h BP and blood pressure at night in the ASA group evening group compared with the ASA morning group and the control group.

Conclusions

The present study demonstrated that compared with the use of ASA in the morning, its administration in the evening may lead to favourable drop in the ABPM and an improvement of the diurnal profile in the high-risk group of cardiovascular patients who are not naïve to ASA.

Electronic supplementary material

The online version of this article (10.1007/s00228-020-02997-8) contains supplementary material, which is available to authorized users.

Effect of Morning vs. Evening Turmeric Consumption on Urine Oxidative Stress Biomarkers in Obese, Middle-Aged Adults: A Feasibility Study

The circadian rhythm of biological systems is an important consideration in developing health interventions. The immune and oxidative defense systems exhibit circadian periodicity, with an anticipatory increase in activity coincident with the onset of the active period. Spice consumption is associated with enhanced oxidative defense. The objective of this study was to test the feasibility of a protocol, comparing the effects of morning vs. evening consumption of turmeric on urine markers of oxidative stress in obese, middle-aged adults. Using a within-sample design, participants received each of four clock time x treatment administrations, each separated by one week: morning turmeric; evening turmeric; morning control; evening control. Participants prepared for each lab visit by consuming a low-antioxidant diet for two days and fasting for 12 h. Urine was collected in the lab at baseline and one-hour post-meal and at home for the following five hours. The results showed that the processes were successful in executing the protocol and collecting the measurements and that participants understood and adhered to the instructions. The findings also revealed that the spice treatment did not elicit the expected antioxidant effect and that the six-hour post-treatment urine collection period did not detect differences in urine endpoints across treatments. This feasibility study revealed that modifications to the spice treatment and urine sampling timeline are needed before implementing a larger study.

Medicine in the Fourth Dimension

The importance of circadian biology has rarely been considered in pre-clinical studies, and even more when translating to the bedside. Circadian biology is becoming a critical factor for improving drug efficacy and diminishing drug toxicity. Indeed, there is emerging evidence showing that some drugs are more effective at nighttime than daytime, whereas for others it is the opposite. This suggests that the biology of the target cell will determine how an organ will respond to a drug at a specific time of the day, thus modulating pharmacodynamics. Thus, it is now time that circadian factors become an integral part of translational research.

Considering Circadian Pattern of Blood Pressure in the Treatment of Hypertension via Chronotherapy: A Conducive or Maladroit Approach

Medical chronobiology deals with the way body's rhythm influences a person's health and disease states. To match body rhythms, deliberate alteration of drug concentration is done to optimize therapeutic outcomes and minimize size effects and this approach is known as Chronotherapeutics. In general the concept of homeostasis has been the base for the treatment of diseases. Little importance has been given in understanding biologic rhythms and their underlying mechanisms. Designing of cardiovascular drug is done to achieve a constant or near-constant effect throughout the 24-hour with the prescribed dose. However in many cases, medication requirement during night and day time are not the same. Body rhythms may have profound effect on the treatment outcomes. It is a wrongful approach to assume that a drug dosed in the morning or evening will have the same antihypertensive effect. The vast literature record of circadian variations in Blood Pressure (BP), heart rate, hormone secretion, and platelet aggregation are examples of the impact of chronobiology. In this study we analyze the effect of circadian pattern of blood pressure on action of various antihypertensives and investigate the perspective of chronotherapeutics- whether it is a fruitful approach and rationalize its utility in the treatment of hypertension.

Aspirin causes endothelium-dependent vasodilation of resistance arteries from non-gravid and gravid rats

OBJECTIVE

The objective of this study was to understand the effect of acetylsalicylic acid (aspirin) on resistance arteries from mesentery and uterus. During pregnancy, the uterine vasculature undergoes consistent growth to provide sufficient uteroplacental blood flow, a process whose failure is associated with pregnancy complications characterized by high uterine vascular resistance.

METHODS

Uterine arcuate (UA) and mesenteric arteries (MA; diameter <300 µm) isolated from non-gravid, mid-gravid (day 14), and late-gravid rats (day 20) were exposed to aspirin (10^-12 to 10^-5 M). Further, in UA from late-gravid rats, aspirin was evaluated in presence of inhibitors of nitric oxide synthases, cyclooxygenase, cyclic nucleotides (cAMP, cGMP) and BK channels, and also on endothelium-denuded vessels.

RESULTS

Aspirin dilated both UA and MA in a dose dependent manner. Pregnancy increased aspirin vasodilation in MA and UA from mid-gravid rats, an effect that was reduced in vessels from late gravid animals at concentrations >10^-7 M. Further, uterine vasodilation was significantly reduced when the endothelium was removed (p < 0.001), and by inhibitors of nitric oxide synthase (p < 0.001), cyclooxygenase synthase (p < 0.05), cyclic nucleotides cGMP/cAMP and BK channels.

CONCLUSION

This is the first study to show a direct vasodilatory effect of aspirin on rat uterine artery that is mediated by a combination of cellular - primarily endothelial - mechanisms. Our results in UA suggest that the use of aspirin may be effective in enhancing uteroplacental blood flow, while its vasodilation effect on MA may lower peripheral resistance.

Time-Dependent Hypotensive Effect of Aspirin in Mice

Objective- Evening but not morning administration of low-dose aspirin has been reported to lower blood pressure in hypertensive patients. The present study was designed to determine whether this phenomenon could be replicated in mice, and if so, whether a time-dependent effect of aspirin on blood pressure was because of alteration of circadian clock function. Approach and Results- We recapitulated the protective effect of aspirin (50 μg/d for 7 days) at zeitgeber time 0 (active-to-rest transit), but not at zeitgeber time 12, on a high-salt diet-induced increase of blood pressure. However, the time of aspirin administration did not influence expression of canonical clock genes or their acetylation. We used mouse Bmal1 and Per2-luciferase reporters expressed in U2OS cells to determine the real-time effect of aspirin on circadian function but found that the oscillation of bioluminescence was unaltered. Timing of aspirin administration also failed to alter urinary prostaglandin metabolites or catecholamines, or the acetylation of its COX-1 (cyclooxygenase-1) target in platelets. Conclusions- The time-dependent hypotensive effect of aspirin in humans has been recapitulated in hypertensive mice. However, this does not seem to reflect a direct impact of aspirin on circadian clocks or on acetylation of platelet COX-1.

Evaluation of the antihypertensive effect of nocturnal administration of acetylsalicylic acid: a cross-over randomized clinical trial

OBJECTIVE

Several studies have shown that evening intake of aspirin has antihypertensive effect in healthy adults, which has not been proven in patients with cardiovascular disease, who mostly take aspirin in the morning. We have evaluated the antihypertensive effect of bedtime administration of aspirin in patients with cardiovascular disease already treated for hypertension.

METHODS

This is a multicenter randomized triple-blind placebo-controlled crossover trial, with hypertensive patients treated with aspirin for secondary prevention. There was a baseline-randomized assignment to 2-month periods of bedtime aspirin (100 mg) first and morning-time aspirin later, or inversely, both periods separated by an open label 2-4 weeks period of morning-time aspirin. At the start and end of each treatment period, a 24-h ambulatory blood pressure monitoring was performed. The main outcome measure was mean 24-h blood pressure. The analyses were performed according to the intention-to-treat principle.

RESULTS

Overall, 225 patients were randomized. No significant differences were observed in ambulatory blood pressure by time of intake of usual low doses of aspirin. The mean SBP/DBP was 123.2/69.9 (95% CI 121.58-124.9/68.86-76.86) with bedtime administration and 122.4/68.8 (95% CI 120.76-124.01/67.85-69.83) with daytime administration (P = 0.3 and P = 0.23 for SBP and DBP, respectively).

CONCLUSION

Administering aspirin at bedtime rather than in the morning does not modify the 24-h ambulatory blood pressure in hypertensive patients in secondary cardiovascular prevention.The trial was registered with ClinicalTrials.gov (number NCT01741922).

Does the timing of aspirin administration influence its antiplatelet effect - review of literature on chronotherapy

This publication is a summary of the multidirectional effects of aspirin and its role in modern medicine. The history of aspirin, or acetylsalicylic acid (ASA), and its use dates back to ancient times, although the substance in its pure form has been produced and sold since 1899. Initially it was used for its antipyretic, analgesic, and anti-inflammatory effects. Over the years many other benefits associated with the administration of ASA have been revealed. The mechanism of aspirin’s action was discovered thanks to the British pharmacologist and Nobel Prize winner Sir John Vane. Understanding the effects of acetylsalicylic acid, associated with the inhibition of cyclooxygenase and proinflammatory thromboxane A2 and with increased concentration of vasoprotective, antithrombotic prostacyclin, gave rise to the era of using small “cardiac” doses of ASA in cardiovascular diseases. In addition to the well-researched antiplatelet effect, other properties of ASA have been discovered, such as the non-COX-1 dependent improvement of endothelial function or the hypotensive effect after evening administration. According to the currently available knowledge, it is possible to speak of a pleiotropic effect of ASA and its use in the prevention of cardiovascular diseases, taking into account its anti-aggregation effect, circadian rhythms, and the principles of chronotherapy.

Coordination of cardiac rhythmic output and circadian metabolic regulation in the heart

Over the course of a 24-h day, demand on the heart rises and falls with the sleep/wake cycles of the organism. Cardiac metabolism oscillates appropriately, with the relative contributions of major energy sources changing in a circadian fashion. The cardiac peripheral clock is hypothesized to drive many of these changes, yet the precise mechanisms linking the cardiac clock to metabolism remain a source of intense investigation. Here we summarize the current understanding of circadian alterations in cardiac metabolism and physiology, with an emphasis on novel findings from unbiased transcriptomic studies. Additionally, we describe progress in elucidating the links between the cardiac peripheral clock outputs and cardiac metabolism, as well as their implications for cardiac physiology.

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.

Effects of Aspirin on Endothelial Function and Hypertension

PURPOSE OF REVIEW

Endothelial dysfunction is intimately related to the development of various cardiovascular diseases, including hypertension, and is often used as a target for pharmacological treatment. The scope of this review is to assess effects of aspirin on endothelial function and their clinical implication in arterial hypertension.

RECENT FINDINGS

Emerging data indicate the role of platelets in the development of vascular inflammation due to the release of proinflammatory mediators, for example, triggered largely by thromboxane. Vascular inflammation further promotes oxidative stress, diminished synthesis of vasodilators, proaggregatory and procoagulant state. These changes translate into vasoconstriction, impaired circulation and thrombotic complications. Aspirin inhibits thromboxane synthesis, abolishes platelets activation and acetylates enzymes switching them to the synthesis of anti-inflammatory substances. Aspirin pleiotropic effects have not been fully elucidated yet. In secondary prevention studies, the decrease in cardiovascular events with aspirin outweighs bleeding risks, but this is not the case in primary prevention settings. Ongoing trials will provide more evidence on whether to expand the use of aspirin or stay within current recommendations.

Sleep-time ambulatory blood pressure as a prognostic marker of vascular and other risks and therapeutic target for prevention by hypertension chronotherapy: Rationale and design of the Hygia Project

This article describes the rationale, objectives, design and conduct of the ambulatory blood pressure monitoring (ABPM)-based Hygia Project. Given the substantial evidence of the significantly better prognostic value of ABPM compared to clinic BP measurements, several international guidelines now propose ABPM as a requirement to confirm the office diagnosis of hypertension. Nonetheless, all previous ABPM outcome investigations, except the Monitorización Ambulatoria para Predicción de Eventos Cardiovasculares study (MAPEC) study, relied upon only a single, low-reproducible 24 h ABPM assessment per participant done at study inclusion, thus precluding the opportunity to explore the potential reduction in cardiovascular disease (CVD) risk associated with modification of prognostic ABPM-derived parameters by hypertension therapy. The findings of the single-center MAPEC study, based upon periodic systematic 48 h ABPM evaluation of all participants during a median follow-up of 5.6 years, constitute the first proof-of-concept evidence that the progressive reduction of the asleep systolic blood pressure (SBP) mean and correction of the sleep-time relative SBP decline toward the normal dipper BP profile, most efficiently accomplished by a bedtime hypertension treatment strategy, best attenuates the risk of CVD, stroke and development of new-onset diabetes. The Hygia Project, primarily designed to extend the use of ABPM in primary care as a requirement for diagnosis of hypertension, evaluation of response to treatment and individualized assessment of CVD and other risks, is a research network presently composed of 40 clinical sites and 292 investigators. Its main objectives are to (i) investigate whether specific treatment-induced changes in ABPM-derived parameters reduce risk of CVD events, stroke, new-onset diabetes and/or development of chronic kidney disease (CKD); and (ii) test the hypothesis that bedtime chronotherapy entailing the entire daily dose of ≥1 conventional hypertension medications exerts better ambulatory BP control and CVD, metabolic and renal risk reduction than all such medications ingested in the morning upon awakening. Between 2007 and 2015, investigators recruited 18 078 persons [9769 men/8309 women, 59.1 ± 14.3 years of age (mean ± SD)], including 15 764 with hypertension according to ABPM criteria as participants in the prospective randomized chronotherapy trial. The initial evaluation includes 48 h ABPM, detailed medical history and screening laboratory blood and urine tests. The same evaluation procedure is scheduled annually, or more frequently when treatment adjustment is required for proper ambulatory BP control, targeting a median follow-up of >5 years. The primary CVD outcome end point is the composite of CVD death, myocardial infarction, coronary revascularization, heart failure, ischemic stroke and hemorrhagic stroke. The independent Hygia Project Events Committee periodically evaluates blinded clinical reports to ascertain and certify every documented event. Beyond the potential findings resulting from testing the main hypotheses, the Hygia Project has already demonstrated, as proof of concept, that the routine diagnosis of hypertension and individualized assessment of CVD and other risks by ABPM, as currently recommended, is fully viable in the primary care setting, where most people with either hypertension, dyslipidemia, type 2 diabetes or CKD receive routine medical attention.

Opportunities for Web-based Drug Repositioning: Searching for Potential Antihypertensive Agents with Hypotension Adverse Events

Background

Drug repositioning refers to the process of developing new indications for existing drugs. As a phenotypic indicator of drug response in humans, clinical side effects may provide straightforward signals and unique opportunities for drug repositioning.

Objective

We aimed to identify drugs frequently associated with hypotension adverse reactions (ie, the opposite condition of hypertension), which could be potential candidates as antihypertensive agents.

Methods

We systematically searched the electronic records of the US Food and Drug Administration (FDA) Adverse Event Reporting System (FAERS) through the openFDA platform to assess the association between hypotension incidence and antihypertensive therapeutic effect regarding a list of 683 drugs.

Results

Statistical analysis of FAERS data demonstrated that those drugs frequently co-occurring with hypotension events were more likely to have antihypertensive activity. Ranked by the statistical significance of frequent hypotension reporting, the well-known antihypertensive drugs were effectively distinguished from others (with an area under the receiver operating characteristic curve > 0.80 and a normalized discounted cumulative gain of 0.77). In addition, we found a series of antihypertensive agents (particularly drugs originally developed for treating nervous system diseases) among the drugs with top significant reporting, suggesting the good potential of Web-based and data-driven drug repositioning.

Conclusions

We found several candidate agents among the hypotension-related drugs on our list that may be redirected for lowering blood pressure. More important, we showed that a pharmacovigilance system could alternatively be used to identify antihypertensive agents and sustainably create opportunities for drug repositioning.

Investigating the effectiveness of different aspirin dosing regimens and the timing of aspirin intake in primary and secondary prevention of cardiovascular disease: protocol for a systematic review

BACKGROUND

Once-daily low-dose aspirin is routinely used for the prevention of secondary events in cardiovascular disease (CVD). The routine use of aspirin in primary prevention of CVD is less clear due to a finer balance between benefits and harms. In addition, the variability in benefit achievable from the prescription of aspirin has led to a growing interest in considering whether there are more effective aspirin regimens than once-daily dosing or whether effectiveness is influenced by the time of day aspirin is taken (chronotherapy). The proposed systematic review will evaluate the evidence on the effects of different aspirin regimens used in terms of number of doses (e.g. split or alternate dosing) or dosing time of aspirin (e.g. morning versus evening) in primary and secondary prevention of CVD.

METHODS/DESIGN

Standard systematic review methodology will be employed for study identification, selection and data extraction. Electronic databases will be searched incorporating terms relating to population and the intervention. No date or language limitations will apply. Systematic reviews and controlled studies comparing different aspirin regimens-in terms of frequency or timing-for primary and/or secondary prevention of CVD will be included. No restrictions on outcome will apply. Quality assessment will be appropriate for each study design. The data will be tabulated and narratively synthesised. Meta-analysis may be undertaken where clinical and methodological homogeneity exists.

DISCUSSION

There are a number of published and ongoing primary studies that investigate the cardiovascular protective effect of different aspirin regimens. However, no systematic review to date has attempted to review the evidence pertaining to aspirin dosing regimens differing in frequency and/or in timing. The proposed systematic review will cover both the above questions and could potentially be beneficial for reconsidering the current practice of managing patients with aspirin in primary care.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42014010596.

Time-Dependent Effects of Aspirin on Blood Pressure and Morning Platelet Reactivity

Aspirin is used for cardiovascular disease (CVD) prevention by millions of patients on a daily basis. Previous studies suggested that aspirin intake at bedtime reduces blood pressure compared with intake on awakening. This has never been studied in patients with CVD. Moreover, platelet reactivity and CVD incidence is highest during morning hours. Bedtime aspirin intake may attenuate morning platelet reactivity. This clinical trial examined the effect of bedtime aspirin intake compared with intake on awakening on 24-hour ambulatory blood pressure measurement and morning platelet reactivity in patients using aspirin for CVD prevention. In this randomized open-label crossover trial, 290 patients were randomized to take 100 mg aspirin on awakening or at bedtime during 2 periods of 3 months. At the end of each period, 24-hour blood pressure and morning platelet reactivity were measured. The primary analysis population comprised 263 (blood pressure) and 133 (platelet reactivity) patients. Aspirin intake at bedtime did not reduce blood pressure compared with intake on awakening (difference systolic/diastolic: −0.1 [95% confidence interval, −1.0, 0.9]/−0.6 [95% confidence interval, −1.2, 0.0] mm Hg). Platelet reactivity during morning hours was reduced with bedtime aspirin intake (difference: −22 aspirin reaction units [95% confidence interval, −35, −9]). The intake of low-dose aspirin at bedtime compared with intake on awakening did not reduce blood pressure of patients with CVD. However, bedtime aspirin reduced morning platelet reactivity. Future studies are needed to assess the effect of this promising simple intervention on the excess of cardiovascular events during the high risk morning hours.

A circadian gene expression atlas in mammals: implications for biology and medicine

To characterize the role of the circadian clock in mouse physiology and behavior, we used RNA-seq and DNA arrays to quantify the transcriptomes of 12 mouse organs over time. We found 43% of all protein coding genes showed circadian rhythms in transcription somewhere in the body, largely in an organ-specific manner. In most organs, we noticed the expression of many oscillating genes peaked during transcriptional "rush hours" preceding dawn and dusk. Looking at the genomic landscape of rhythmic genes, we saw that they clustered together, were longer, and had more spliceforms than nonoscillating genes. Systems-level analysis revealed intricate rhythmic orchestration of gene pathways throughout the body. We also found oscillations in the expression of more than 1,000 known and novel noncoding RNAs (ncRNAs). Supporting their potential role in mediating clock function, ncRNAs conserved between mouse and human showed rhythmic expression in similar proportions as protein coding genes. Importantly, we also found that the majority of best-selling drugs and World Health Organization essential medicines directly target the products of rhythmic genes. Many of these drugs have short half-lives and may benefit from timed dosage. In sum, this study highlights critical, systemic, and surprising roles of the mammalian circadian clock and provides a blueprint for advancement in chronotherapy.

Protocol for assessing the hypotensive effect of evening administration of acetylsalicylic acid: study protocol for a randomized, cross-over controlled trial

BACKGROUND

The objective of this study is to evaluate the antihypertensive effect of bedtime administration of low doses of aspirin in patients with treated hypertension and high cardiovascular risk on low-dose aspirin for secondary prevention, in order to optimize their usual treatment and reduce their cardiovascular risk.

METHODS/DESIGN

This is a prospective phase IV multicentre, randomised, triple-blind, placebo-controlled, cross-over clinical trial. We will include 258 individuals with hypertension treated with low-dose aspirin for secondary prevention. These patients will be randomly recruited, by approximately 40 primary care physicians collaborating in the study, mainly in the Guipúzcoa West, Bilbao and Barcelona areas. The 258 patients will be randomly allocated to treatments to create two comparable groups. In the first period, the intervention group will take aspirin at night and placebo in the morning, while the control group will take their aspirin in the morning and placebo in the evening for 2 months. After a washout period of 15 to 30 days, there will be a second 2-month period for which groups will swap treatments. Participants will undergo ambulatory blood pressure monitoring at baseline, at the end of first period and then again at the beginning and end of the second period. The main outcome measure is the change in mean blood pressure over 24 h, and as secondary outcomes we will also assess changes in systolic and diastolic blood pressure, during the day and night, and the relationship between them. Lastly, we will explore whether non-dipper patients convert into dippers with the intervention.

DISCUSSION

The goal of this research is to provide the scientific basis for indicating a change in the time of aspirin administration from morning to evening, by primary health practitioners, to improve the patient control of blood pressure and more effectively reduce their cardiovascular risk, by combining this hypotensive effect with the well-known anti-platelet effect of low-dose aspirin.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01741922.

High-dose, but not low-dose, aspirin impairs anticontractile effect of ticagrelor following ADP stimulation in rat tail artery smooth muscle cells

Objective. To compare effects of low- versus high-dose aspirin coadministered with ticagrelor on the reactivity of vascular smooth muscle cells (VSMCs). Methods. Wistar rats were orally administered ticagrelor (10 mg/kg) and/or aspirin (2 or 10 mg/kg) (n = 7 per each of 4 groups) or placebo (n = 9) 12 and 2 hours before experiments. Anticontractile effects of ticagrelor were assessed in perfusion solution containing ticagrelor (1 μM/L). Changes in perfusion pressure proportional to the degree of adenosine diphosphate analogue- (2-MeS-ADP-) and phenylephrine-induced constriction of rat tail arteries were evaluated. Results. Pretreatment with high- but not low-dose aspirin enhanced the reactivity of VSMCs only in endothelium-lined vessels. Suppression of 2-MeS-ADP-induced VSMC contraction by ticagrelor observed in arteries with and without endothelium was maintained in endothelialized arteries pretreated only with low-dose aspirin. For endothelium-denuded vessels and low-dose aspirin we observed a significant reduction of the maximal effect of ticagrelor with no rightward shift of the concentration-response curve for phenylephrine. With high-dose aspirin pretreatment ticagrelor exerted no anticontractile effect. Conclusion. High-dose, but not low-dose, aspirin impairs the anticontractile effect of ticagrelor on ADP-induced VSMC contraction in the rat model. Both the clinical significance and detailed underlying mechanism of our findings require further investigation.

Biological rhythms and preeclampsia

The impact of impaired circadian rhythm on health has been widely studied in shift workers and trans-meridian travelers. A part from its correlation with sleep and mood disorders, biological rhythm impairment is a recognized risk factor for cardiovascular diseases and breast cancer. Preeclampsia is a major public health issue, associated with a significant maternal and fetal morbidity and mortality worldwide. While the risks factors for this condition such as obesity, diabetes, pre-existing hypertension have been identified, the underlying mechanism of this multi-factorial disease is yet not fully understood. The disruption of the light/dark cycle in pregnancy has been associated with adverse outcomes. Slightly increased risk for "small for gestational age" babies, "low birth weight" babies, and preterm deliveries has been reported in shift working women. Whether altered circadian cycle represents a risk factor for preeclampsia or preeclampsia is itself linked with an abnormal circadian cycle is less clear. There are only few reports available, showing conflicting results. In this review, we will discuss recent observations concerning circadian pattern of blood pressure in normotensive and hypertensive pregnancies. We explore the hypothesis that circadian misalignments may represent a risk factor for preeclampsia. Unraveling potential link between circadian clock gene and preeclampsia could offer a novel approach to our understanding of this multi-system disease specific to pregnancy.

Acetylsalicylic acid regulates overexpressed small GTPase RhoA in vascular smooth muscle cells through prevention of new synthesis and enhancement of protein degradation

RhoA has been shown to play a major role in vascular processes and acetylsalicylic acid (aspirin) is known to exert a cytoprotective effect via multiple mechanisms. In the present study, we aimed at investigating the effect of aspirin on RhoA expression under a stress state in rat VSMCs (vascular smooth muscle cells) and the underlying mechanisms. The expression of iNOS (inducible nitric oxide synthase) and iNOS activity as well as NO concentration was significantly promoted by LPS (lipopolysaccharide) accompanying the elevation of RhoA expression, which was blocked by the addition of the iNOS inhibitor L-NIL [L-N6-(1-iminoethyl)lysine dihydrochloride]. Aspirin (30 μM) significantly attenuated the elevation of RhoA, while indomethacin and salicylate had no similar effect. The sGC (soluble guanylate cyclase) inhibitor ODQ (1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one) showed the same effect as aspirin in down-regulating RhoA but was reversed by the addition of the cGMP analogue 8-Br-PET-cGMP (β-phenyl-1,N2-ethano-8-bromoguanosine 3',5'-cyclic monophosphorothioate). 8-Br-PET-cGMP solely enhanced the RhoA expression that was abrogated by preincubation with aspirin. Degradation analysis indicated that aspirin enhanced the protein degradation rate of RhoA and GDP-bound RhoA seemed to be more susceptible to aspirin-enhanced degradation compared with the GTP-bound form. Our results indicate that aspirin attenuates the LPS-induced overexpression of RhoA both by inhibiting new synthesis and accelerating protein degradation, which may help elucidate the multiple beneficial effects of aspirin.

Evening versus morning dosing regimen drug therapy for hypertension

BACKGROUND

Variation in blood pressure levels display circadian rhythms. The morning surge in blood pressure is known to increase the risk of myocardial events in the first several hours post awakening. A systematic review of the administration-time-related-effects of evening versus morning dosing regimen of antihypertensive drugs in the management of patients with primary hypertension has not been conducted.

OBJECTIVES

To evaluate the administration-time-related-effects of antihypertensive drugs administered as once daily monotherapy in the evening versus morning administration regimen on all cause mortality, cardiovascular morbidity and reduction of blood pressure in patients with primary hypertension.

SEARCH STRATEGY

We searched Cochrane CENTRAL on Ovid (4th Quarter 2009), Ovid MEDLINE (1950 to October 2009), EMBASE (1974 to October 2009), the Chinese Biomedical literature database (1978 to 2009) and the reference lists of relevant articles. No language restrictions were applied.

SELECTION CRITERIA

Randomized controlled trials comparing the administration-time-related effects of evening with morning dosing monotherapy regimens in patients with primary hypertension were included. Patients with known secondary hypertension, shift workers or white coat hypertension were excluded.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data and assessed trial quality. Disagreements were resolved by discussion or a third reviewer. Data synthesis and analysis were done using RevMan 5.1. Random effects meta-analysis and sensitivity analysis were conducted.

MAIN RESULTS

21 randomized controlled trials (RCTs) in 1,993 patients with primary hypertension met the inclusion criteria for this review - ACEIs (5 trials), CCBs (7 trials), ARBs (6 trials), diuretics (2 trials), alpha-blockers (1 trial), and beta-blockers (1 trial). Meta-analysis showed significant heterogeneity across trials.No RCT reported on all cause mortality, cardiovascular mortality, cardiovascular morbidity and serious adverse events.There was no statistically significant difference for overall adverse events (RR=0.78, 95%CI: 0.37 to 1.65) and withdrawals due to adverse events (RR=0.53, 95%CI: 0.26 to 1.07).No significant differences were noted for morning SBP (-1.62 mm Hg, 95% CI: -4.19 to 0.95) and morning DBP (-1.21 mm Hg, 95% CI: -3.28 to 0.86); but 24-hour BP (SBP: -1.71 mm Hg, 95% CI: -2.78 to -0.65; DBP: -1.38 mm Hg, 95% CI: -2.13 to -0.62) showed a statistically significant difference.

AUTHORS' CONCLUSIONS

No RCT reported on clinically relevant outcome measures - all cause mortality, cardiovascular morbidity and morbidity. There were no significant differences in overall adverse events and withdrawals due to adverse events among the evening versus morning dosing regimens. In terms of BP lowering efficacy, for 24-hour SBP and DBP, the data suggests that better blood pressure control was achieved with bedtime dosing than morning administration of antihypertensive medication, the clinical significance of which is not known.

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.

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.

Ambulatory blood pressure control with bedtime aspirin administration in subjects with prehypertension

BACKGROUND

Aspirin has been found to prevent angiotensin II-induced hypertension and to induce nitric oxide (NO) release from vascular endothelium. Low-dose aspirin has also been shown to reduce blood pressure (BP) when administered at bedtime, as opposed to upon awakening, in untreated hypertensive patients and high-risk pregnant women. Accordingly, we investigated the effects on ambulatory BP of aspirin administered at different times of the day in prehypertension.

METHODS

We studied 244 subjects with prehypertension, 43.0 +/- 13.0 years of age, randomly divided in three groups: nonpharmacological hygienic-dietary recommendations; the same recommendations and aspirin (100 mg/day) on awakening; or the same recommendations and aspirin at bedtime. BP was measured for 48 consecutive hours before and after 3 months of intervention.

RESULTS

Ambulatory BP was unchanged in subjects randomized to either nonpharmacological intervention or aspirin on awakening. A significant ambulatory BP reduction was, however, observed in the subjects who received aspirin at bedtime (decrease of 6/3 mm Hg in the 24-h mean of systolic (SBP)/diastolic BP (DBP), respectively; P < 0.001), without changes in heart rate (HR) from baseline. BP was homogeneously controlled along the 24 h after bedtime aspirin administration (6/4 mm Hg reduction in activity mean of SBP/DBP; 6/3 mm Hg reduction in sleep-time mean, respectively).

CONCLUSIONS

This prospective trial documents a significant effect on BP of low dose aspirin only when ingested at bedtime by prehypertensive subjects. The timed administration of low-dose aspirin could thus provide a valuable and cost-effective approach for BP control in subjects at elevated risk of developing hypertension.

Salicylates dilate blood vessels through inhibiting PYK2-mediated RhoA/Rho-kinase activation

AIMS

Compared with other non-steroid anti-inflammatory drugs (NSAIDs), aspirin is not correlated to hypertension. It has been shown that aspirin has unique vasodilator action in vivo, offering an explanation for the unique blood pressure effect of aspirin. In the present study, we investigate the mechanism whereby salicylates (aspirin and sodium salicylate) dilate blood vessels.

METHODS AND RESULTS

Rat aortic or mesenteric arterial rings were used to test the vascular effect of salicylates and other NSAIDs. RhoA translocation and the phosphorylation of MYPT1, the regulatory subunit of myosin light chain phosphatase, were measured by western blot, as evidenced for RhoA/Rho-kinase activation. Salicylates, but not other NSAIDs, relaxed contraction induced by most tested constrictors except for calyculin A, indicating that RhoA/Rho-kinase-mediated calcium sensitization is involved. The involvement of RhoA/Rho kinase in vasodilation by salicylates was confirmed by measurements of RhoA translocation and MYPT1 phosphorylation. The calculated half maximal inhibitory concentration (IC(50)) of vasodilation was apparently higher than that of cyclooxygenase inhibition, but comparable to that of proline-rich tyrosine kinase 2 (PYK2) inhibition. Over-expression of PYK2 induced RhoA translocation and MYPT1 phosphorylation, and these effects were markedly inhibited by sodium salicylate treatment. Consistent with the ex vitro vascular effects, sodium salicylate acutely decreased blood pressure in spontaneous hypertensive rats but not in Wistar Kyoto rats.

CONCLUSION

Salicylates dilate blood vessels through inhibiting PYK2-mediated RhoA/Rho-kinase activation and thus lower blood pressure.

Optimal time to take once-daily oral medications in clinical practice

Currently only a few package inserts of once-daily medications specially define the dosing time, although sporadic studies have demonstrated administration time-dependent effects on the therapeutic outcome. Some chronotherapeutic approaches aim to diminish the occurrence of adverse drug reactions (ADRs) and hence better tolerance and medication compliance whereas most of the chronotherapies are recommended to improve therapeutic efficacy. The administration time-dependent efficacy seems not a common feature of drugs within the similar therapeutic or structural class and it is related to kinds of drugs, pathophysiologic status, clinical symptoms and feedback from patients. Doctors, pharmacists and nurses should know what kind of drug has requirement for optimal dosing time, and realize that better efficacy and lower incidence of ADRs may be achieved by rational arrangement of administration schedule. In order to promote medication compliance, it is essential to provide patient education regarding differences between conventional and chronotherapeutic approaches and pathophysiologic benefits of chronotherapy.

Should pulse pressure and day/night variations in blood pressure be seen as independent risk factors requiring correction or simply as markers to be taken into account when evaluating overall vascular risk?

Patients with a blunted fall in nocturnal BP (known as non-dippers) have a high risk of micro- and macrovascular complications, particularly if they have hypertension, but also in normotensive patients with diabetes. A blunted fall in nocturnal BP reflects the high level of CV risk in these patients. ABPM data indicating an altered circadian BP rhythm reverse circadian BP profile should alert the physician to the potential risk of complications and should lead to efforts to treat hypertension effectively, especially at night, and to check for sleep apnoea syndrome, particularly in cases of resistant hypertension, or autonomic neuropathy (postural hypotension), a well known risk factor for cardiovascular (CV) events. Patients should be carefully screened for nephropathy. However, the definitions of "non-dipper" vary widely. Suitable treatments are poorly defined, but angiotensin-converting enzyme inhibitors (ACEi), diuretics, salt restriction and the maintenance of continuous positive airway pressure (CPAP) can be used as non-specific treatments. The efficacy of taking blood pressure-lowering drugs at bedtime rather than in the morning is still debated but deserves attention. In the diabetic population, brachial pulse pressure (PP) is an independent predictor of cardiovascular mortality, but not of all-cause mortality. It is also associated with complications of both type 2 and type 1 diabetes, this effect being stronger for nocturnal than for diurnal PP, and is strongly predictive of coronary heart disease in patients with type 2 diabetes. The stronger association between PP and age in diabetic than in non-diabetic populations suggests that diabetes accelerates vascular ageing. In patients with incipient nephropathy or overt renal failure, PP increases CV risk. However, misinterpretation could be related to confusion between brachial PP and central PP. The therapeutic implications of PP measurement remain poorly documented in diabetes.

Chronotherapy of hypertension: administration-time-dependent effects of treatment on the circadian pattern of blood pressure

Some specific features of the 24-hour blood pressure (BP) pattern are linked to the progressive injury of target tissues and the triggering of cardiac and cerebrovascular events. Thus, there is growing interest in how to best tailor the treatment of hypertensive patients according to the circadian BP pattern of each individual. Significant administration-time differences in the kinetics (i.e., chronokinetics) plus beneficial and adverse effects (i.e., chronodynamics) of antihypertensive medications are well known. Thus, bedtime dosing with nifedipine GITS is more effective than morning dosing, while also significantly reducing adverse effects. The dose-response curve, therapeutic coverage, and efficacy of doxazosin GITS are all markedly dependent on the circadian time of drug administration. Moreover, valsartan administration at bedtime, as opposed to upon wakening, results in an improved diurnal/nocturnal BP ratio, increased percentage of controlled patients, and significant reduction in urinary albumin excretion in hypertensive patients. Chronotherapy provides a means of individualizing the treatment of hypertension according to the circadian BP profile of each patient, and constitutes a new option to optimize BP control and to reduce the risk of cardiovascular disease (myocardial infarction and stroke) and of end-organ injury of the blood vessels and tissue of the heart, brain, kidney, eye, and other organs.

Medication administration discrepancies persist despite electronic ordering

Background Up to 38% of inpatient medication errors occur at the administration stage. Although they reduce prescribing errors, computerized provider order entry (CPOE) systems do not prevent administration errors or timing discrepancies. This study determined the degree to which CPOE medication orders matched actual dose administration times. METHODS At a 658-bed academic hospital with CPOE but lacking electronic medication administration charting, authors randomly selected adult patients with eligible medication orders from historical 1999-2003 CPOE log files. Retrospective manual chart audits compared expected (from CPOE) and actual timing of medication administrations. Outcomes included: dose omissions, median lag times between ordered and charted administrations, unauthorized doses, wrong dose errors, and the rate of nurses' medication schedule shifting. RESULTS Dose omissions occurred in 756 of 6019 (12.6%) audited administration opportunities; only 313 of the omissions (5.2% of opportunities) were unexplained. Wrong doses and unexpected doses occurred for 0.1% and 0.7% of opportunities, respectively. Median lag from expected first dose to actual charted administration time was 27 minutes (IQR 0-127). Nursing staff shifted from ordered to alternate administration schedules for 10.7% of regularly scheduled recurring medication orders. Chart review identified reasons for dose omissions, delays, and dose shifting. CONCLUSION Inpatient CPOE orders are legible and conveyed electronically to nurses and the pharmacy. Nonetheless, ward-based medication administrations do not consistently occur as ordered. Medication administration discrepancies are likely to persist even after implementing CPOE and bar-coded medication administration unless recommended interventions are made to address issues such as determining the true urgency of medication administration, avoiding overlapping duplicative medication orders, and developing a safe means for shifting dosing schedules.

Chronotherapy in hypertensive patients: administration-time dependent effects of treatment on blood pressure regulation

Ambulatory blood pressure measurements (ABPM) correlate more closely with target organ damage and cardiovascular events than clinical cuff measurements. ABPM reveals the significant circadian variation in BP, which in most individuals presents a morning increase, small post-prandial decline, and more extensive lowering during nocturnal rest. However, under certain pathophysiological conditions, the nocturnal BP decline may be reduced (nondipper pattern) or even reversed (riser pattern). This is clinically relevant since the nondipper and riser circadian BP patterns constitute a risk factor for left ventricular hypertrophy, microalbuminuria, cerebrovascular disease, congestive heart failure, vascular dementia and myocardial infarction. Hence, there is growing interest in how to best tailor and individualize the treatment of hypertension according to the circadian BP pattern of each patient. Significant administration-time differences in the kinetics and in the beneficial and adverse effects of antihypertensive medications are well known. Thus, bedtime dosing with nifedipine gastrointestinal therapeutic system (GITS) is more effective than morning dosing, while also significantly reducing adverse effects. The therapeutic coverage and efficacy of doxazosin GITS are dependent on the circadian time of drug administration. Moreover, valsartan administration at bedtime, as opposed to upon wakening, results in an improved diurnal/nocturnal BP ratio, increased percentage of controlled patients, and significant reduction in urinary albumin excretion in hypertensive patients. Chronotherapy provides a means of individualizing the treatment of hypertension according to the circadian BP profile of each patient, and constitutes a new option to optimize BP control and reduce the risk of cardiovascular disease.

[Sequelae of hypertenson: kidney disease]

Nephropathy is one of the frequent sequelae of hypertension. Arterial hypertension causes both arterial and capillary changes in the kidneys as well as development of interstitial fibrosis. Systemic or intraglomerular pressure increase leads to albuminuria and proteinuria, which in turn contributes to further damage of the kidneys. Impairment of the kidneys due to hypertension can ultimately result in terminal renal insufficiency necessitating dialysis. Metabolic factors such as hyperlipidemia, hyperuricemia, hyperhomocysteinemia, and insulin resistance can aggravate renal lesions. Effective lowering of blood pressure in conjunction with management of the metabolic risk factors is decisive for prevention of chronic kidney disease, which in turn must be considered a factor involved in exacerbation of the hypertension.