Fixed-combination of amlodipine and diuretic chronotherapy in the treatment of essential hypertension: improved blood pressure control with bedtime dosing-a multicenter, open-label randomized study

Insight on Cardiac Chronobiology and Latest Developments of Chronotherapeutic Antihypertensive Interventions for Better Clinical Outcomes

Cardiac circadian rhythms are an important regulator of body functions, including cardiac activities and blood pressure. Disturbance of circadian rhythm is known to trigger and aggravate various cardiovascular diseases. Thus, modulating the circadian rhythm can be used as a therapeutic approach to cardiovascular diseases. Through this work, we intend to discuss the current understanding of cardiac circadian rhythms, in terms of quantifiable parameters like BP and HR. We also elaborate on the molecular regulators and the molecular cascades along with their specific genetic aspects involved in modulating circadian rhythms, with specific reference to cardiovascular health and cardiovascular diseases. Along with this, we also presented the latest pharmacogenomic and metabolomics markers involved in chronobiological control of the cardiovascular system along with their possible utility in cardiovascular disease diagnosis and therapeutics. Finally, we reviewed the current expert opinions on chronotherapeutic approaches for utilizing the conventional as well as the new pharmacological molecules for antihypertensive chronotherapy.

Current Knowledge about the New Drug Firibastat in Arterial Hypertension

Hypertension significantly increases the risk of cardiovascular disease. Currently, effective standard pharmacological treatment is available in the form of diuretics, ACE inhibitors, angiotensin II receptor blockers and calcium channel blockers. These all help to decrease blood pressure in hypertensive patients, each with their own mechanism. Recently, firibastat, a new first-in-class antihypertensive drug has been developed. Firibastat is a prodrug that when crossing the blood-brain barrier, is cleaved into two active EC33 molecules. EC33 is the active molecule that inhibits the enzyme aminopeptidase A. Aminopeptidase A converts angiotensin II to angiotensin III. Angiotensin III usually has three central mechanisms that increase blood pressure, so by inhibiting this enzyme activity, a decrease in blood pressure is seen. Firibastat is an antihypertensive drug that affects the brain renin angiotensin system by inhibiting aminopeptidase A. Clinical trials with firibastat have been performed in animals and humans. No severe adverse effects related to firibastat treatment have been reported. Results from studies show that firibastat is generally well tolerated and safe to use in hypertensive patients. The aim of this review is to investigate the current knowledge about firibastat in the treatment of hypertension.

Ingestion-time differences in the pharmacodynamics of dual-combination hypertension therapies: Systematic review and meta-analysis of published human trials

The pharmacodynamics of hypertension medications can be significantly affected by circadian rhythms in the biological mechanisms of the 24 h blood pressure (BP) pattern. Hypertension guidelines fail to recommend the time of day when patients, including those who require treatment with multiple medications, are to ingest BP-lowering therapy. We conducted a systematic review of published prospective trials that investigated hypertension medications for ingestion-time differences in BP-lowering, safety, patient adherence, and markers of target organ pathology. Among the search-retried 155 trials, 17 published between 1991 and 2020 totaling 1,508 hypertensive participants concerned the differential ingestion-time dependent effects of 14 unique dual-combination therapies. All but one (94.1%) of the trials, involving 98.5% of the total number of investigated individuals, reported clinically and statistically significant benefits - including enhanced reduction of asleep BP without induction of sleep-time hypotension, reduced prevalence of BP non-dipping, decreased adverse effects, improved kidney function, and reduced cardiac pathology - when dual-combination hypertension medications were ingested at-bedtime/evening rather than upon-waking/morning. A systematic and comprehensive review of the literature published in the past three decades reveals no single dual-combination hypertension trial reported significantly better benefit of the still conventional, yet unjustified by medical evidence, upon-waking/morning hypertension treatment scheme.

COVID-19: Sleep, Circadian Rhythms and Immunity - Repurposing Drugs and Chronotherapeutics for SARS-CoV-2

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has affected nearly 28 million people in the United States and has caused more than five hundred thousand deaths as of February 21, 2021. As the novel coronavirus continues to take its toll in the United States and all across the globe, particularly among the elderly (>65 years), clinicians and translational researchers are taking a closer look at the nexus of sleep, circadian rhythms and immunity that may contribute toward a more severe coronavirus disease-19 (COVID-19). SARS-CoV-2-induced multi-organ failure affects both central and peripheral organs, causing increased mortality in the elderly. However, whether differences in sleep, circadian rhythms, and immunity between older and younger individuals contribute to the age-related differences in systemic dysregulation of target organs observed in SARS-CoV-2 infection remain largely unknown. Current literature demonstrates the emerging role of sleep, circadian rhythms, and immunity in the development of chronic pulmonary diseases and respiratory infections in human and mouse models. The exact mechanism underlying acute respiratory distress syndrome (ARDS) and other cardiopulmonary complications in elderly patients in combination with associated comorbidities remain unclear. Nevertheless, understanding the critical role of sleep, circadian clock dysfunction in target organs, and immune status of patients with SARS-CoV-2 may provide novel insights into possible therapies. Chronotherapy is an emerging concept that is gaining attention in sleep medicine. Accumulating evidence suggests that nearly half of all physiological functions follow a strict daily rhythm. However, healthcare professionals rarely take implementing timed-administration of drugs into consideration. In this review, we summarize recent findings directly relating to the contributing roles of sleep, circadian rhythms and immune response in modulating infectious disease processes, and integrate chronotherapy in the discussion of the potential drugs that can be repurposed to improve the treatment and management of COVID-19.

Extent of asleep blood pressure reduction by hypertension medications is ingestion-time dependent: Systematic review and meta-analysis of published human trials

Combined evidence of published prospective outcome trials and meta-analyses substantiate elevated asleep blood pressure (BP) and blunted sleep-time relative BP decline (non-dipping), regardless of wake-time office BP and awake or 24 h BP means, are jointly the most highly significant independent prognostic markers of cardiovascular disease (CVD) risk and worthy therapeutic targets for prevention. Nonetheless, current guidelines continue to recommend the diagnosis of hypertension, when based on ambulatory BP monitoring (ABPM), rely, solely, on either the 24 h or "daytime" BP means. They also fail to recommend the time to treat patients. We conducted a systematic review of published human trials regarding ingestion-time differences in the effects of hypertension medications on asleep BP and sleep-time relative BP decline. Some 62 such trials published between 1992 and 2020, totaling 6120 hypertensive persons, evaluated 21 different single and 8 dual-fixed combination therapies. The vast (82.3%) majority of the trials substantiate the bedtime/evening vs. upon-waking/morning treatment schedule produces statistically significant better clinical benefits, including enhanced reduction of asleep systolic BP by an average 5.17 mmHg (95%CI [4.04, 6.31], P < 0.001 between treatment-time groups) without inducing sleep-time hypotension, reduced prevalence of the high CVD risk non-dipper 24 h BP pattern, improved kidney function, and reduced cardiac pathology. Furthermore, systematic and comprehensive review of the ABPM-based literature published the past 29 years reveals no single study that reported significantly better benefits of the most recommended, yet unjustified by medical evidence, morning hypertension treatment-time scheme.

Circadian Variation in Efficacy of Medications

Although much has been learned about circadian clocks and rhythms over the past few decades, translation of this foundational science underlying the temporal regulation of physiology and behavior to clinical applications has been slow. Indeed, acceptance of the modern study of circadian rhythms has been blunted because the phenomenology of cyclic changes had to counteract the 20th century dogma of homeostasis in the biological sciences and medicine. We are providing this review of clinical data to highlight the emerging awareness of circadian variation in efficacy of medications for physicians, clinicians, and pharmacists. We are suggesting that gold-standard double-blind clinical studies should be conducted to determine the best time of day for optimal effectiveness of medications; also, we suggest that time of day should be tracked and reported as an important biological variable in ongoing clinical studies hereafter. Furthermore, we emphasize that time of day is, and should be considered, a key biological variable in research design similar to sex. In common with biomedical research data that have been historically strongly skewed toward the male sex, most pharmaceutical data have been skewed toward morning dosing without strong evidence that this is the optimal time of efficacy.

Current evidence on the circadian-time-dependent effects of hypertension medications and their combinations in relation to findings of MAPEC and Hygia Chronotherapy Trial

The main purpose of this commentary is to update, based on our extensive review of the published literature of the past 45 yrs, the differential therapeutic effects of hypertension medications of various classes and their combinations when ingested in the evening/at-bedtime versus in the morning/upon-awakening. Interestingly, revision of the currently available evidence on the differential circadian-time-dependent effects of hypertension medications of six different classes and their combinations indicates among the 137 published hypertension medication trials that evaluated blood pressure (BP)-lowering efficacy according to treatment-time, 112 (81.75%) documented significant better benefits by evening/bedtime compared to morning/awakening-scheduled therapy. The remaining 25 published trials found no treatment-time difference in effects; indeed, no single study has reported better benefits of the still conventional, but scientifically unjustified, morning than evening/at-bedtime treatment scheme.

Cardiovascular diseases: a therapeutic perspective around the clock

Biological rhythms are a ubiquitous feature of life. Most bodily functions, including physiological, biochemical, and behavioral processes, are coupled by the circadian rhythm. In the cardiovascular system, circadian fluctuations regulate several functions, namely heart rate, blood pressure, cardiac contractility, and metabolism. In fact, current lifestyles impose external timing constraints that clash with our internal circadian physiology, often increasing the risk of cardiovascular disease (CVD). Still, the mechanisms of dysregulation are not fully understood because this is a growing area of research. In this review, we explore the modulatory role of the circadian rhythms on cardiovascular function and disease as well as the role of chronotherapy in the context of CVD and how such an approach could improve existing therapies and assist in the development of new ones.

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.

Circadian clock-mediated regulation of blood pressure

Most bodily functions vary over the course of a 24h day. Circadian rhythms in body temperature, sleep-wake cycles, metabolism, and blood pressure (BP) are just a few examples. These circadian rhythms are controlled by the central clock in the suprachiasmatic nucleus (SCN) of the hypothalamus and peripheral clocks located throughout the body. Light and food cues entrain these clocks to the time of day and this synchronicity contributes to the regulation of a variety of physiological processes with effects on overall health. The kidney, brain, nervous system, vasculature, and heart have been identified through the use of mouse models and clinical trials as peripheral clock regulators of BP. The dysregulation of this circadian pattern of BP, with or without hypertension, is associated with increased risk for cardiovascular disease. The mechanism of this dysregulation is unknown and is a growing area of research. In this review, we highlight research of human and mouse circadian models that has provided insight into the roles of these molecular clocks and their effects on physiological functions. Additional tissue-specific studies of the molecular clock mechanism are needed, as well as clinical studies including more diverse populations (different races, female patients, etc.), which will be critical to fully understand the mechanism of circadian regulation of BP. Understanding how these molecular clocks regulate the circadian rhythm of BP is critical in the treatment of circadian BP dysregulation and hypertension.

Bedtime Blood Pressure Chronotherapy Significantly Improves Hypertension Management

Consistent evidence of numerous studies substantiates the asleep blood pressure (BP) mean derived from ambulatory BP monitoring (ABPM) is both an independent and a stronger predictor of cardiovascular disease (CVD) risk than are daytime clinic BP measurements or the ABPM-determined awake or 24-hour BP means. Hence, cost-effective adequate control of sleep-time BP is of marked clinical relevance. Ingestion time, according to circadian rhythms, of hypertension medications of 6 different classes and their combinations significantly improves BP control, particularly sleep-time BP, and reduces adverse effects.

Fixed-Dose Triple Combination of Antihypertensive Drugs Improves Blood Pressure Control: From Clinical Trials to Clinical Practice

INTRODUCTION

Blood pressure (BP) control is the main clinical goal in the management of hypertensive patients; however, BP in most of these patients remains uncontrolled, despite the widespread availability of antihypertensive drugs as free-combination therapy. This study compared the efficacy of a fixed-dose triple combination (FDTC) of antihypertensive drugs with that of a free combination of three antihypertensives in patients with uncontrolled hypertension.

METHODS

Ninety-two patients (mean age 60.8 ± 12.1, 58.0% male) with uncontrolled essential hypertension (office systolic BP ≥ 140 or diastolic BP ≥ 90 mmHg) previously treated with a renin-angiotensin-aldosterone system (RAAS) inhibitor plus hydrochlorothiazide were switched to once-daily FDTC therapy with perindopril/indapamide/amlodipine (5-10/1.25-2.5/5-10 mg). Patients were age- and sex-matched with a control group of hypertensive patients receiving free-combination therapy with three drugs including a RAAS inhibitor, a diuretic, and a calcium channel blocker. Office BP and 24-h ambulatory BP monitoring (ABPM) were evaluated at baseline and after 1 and 4 months.

RESULTS

Significant reductions in ambulatory 24-h, daytime, and nighttime systolic BP, and pulse pressure (PP) were found in the FDTC group relative to reductions seen with free-combination therapy, after the first month only of follow-up. Target BP values (mean 24-h ambulatory systolic/diastolic BP < 130/80 mmHg) were reached by more recipients of FDTC than free-combination therapy (64.8% vs. 46.9%, p < 0.05) at month 4 of follow-up, despite reductions in 24-h ABPM values from baseline being similar in both groups at this time point.

CONCLUSION

FDTC of perindopril/indapamide/amlodipine was effective at reducing SBP and PP in previously treated patients with uncontrolled hypertension, and well tolerated, providing support for clinicians in choosing a fixed-dose triple combination over the free-combination of a RAAS inhibitor, a diuretic, and a calcium antagonist.

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.

Timing of Administration: For Commonly-Prescribed Medicines in Australia

Chronotherapy involves the administration of medication in coordination with the body's circadian rhythms to maximise therapeutic effectiveness and minimise/avoid adverse effects. The aim of this study is to investigate the "time of administration" recommendations on chronotherapy for commonly-prescribed medicines in Australia. This study also aimed to explore the quality of information on the timing of administration presented in drug information sources, such as consumer medicine information (CMI) and approved product information (PI). Databases were searched for original research studies reporting on the impact of "time of administration" of the 30 most commonly-prescribed medicines in Australia for 2014. Further, time of administration recommendations from drug information sources were compared to the evidence from chronotherapy trials. Our search revealed 27 research studies, matching the inclusion and exclusion criteria. In 56% (n = 15) of the research studies, the therapeutic effect of the medicine varied with the time of administration, i.e., supported chronotherapy. For some medicines (e.g., simvastatin), circadian-based optimal administration time was evident in the information sources. Overall, dedicated studies on the timing of administration of medicines are sparse, and more studies are required. As it stands, information provision to consumers and health professionals about the optimal "time" to take medications lags behind emerging evidence.

Glucocorticoids Induce Nondipping Blood Pressure by Activating the Thiazide-Sensitive Cotransporter

Supplemental Digital Content is available in the text.

Blood pressure (BP) normally dips during sleep, and nondipping increases cardiovascular risk. Hydrochlorothiazide restores the dipping BP profile in nondipping patients, suggesting that the NaCl cotransporter, NCC, is an important determinant of daily BP variation. NCC activity in cells is regulated by the circadian transcription factor per1. In vivo, circadian genes are entrained via the hypothalamic–pituitary–adrenal axis. Here, we test whether abnormalities in the day:night variation of circulating glucocorticoid influence NCC activity and BP control. C57BL6/J mice were culled at the peak (1:00 AM) and trough (1:00 PM) of BP. We found no day:night variation in NCC mRNA or protein but NCC phosphorylation on threonine⁵³ (pNCC), required for NCC activation, was higher when mice were awake, as was excretion of NCC in urinary exosomes. Peak NCC activity correlated with peak expression of per2 and bmal1 (clock genes) and sgk1 and tsc22d3 (glucocorticoid-responsive kinases). Adrenalectomy reduced NCC abundance and blunted the daily variation in pNCC levels without affecting variation in clock gene transcription. Chronic corticosterone infusion increased bmal1, per1, sgk1, and tsc22d3 expression during the inactive phase. Inactive phase pNCC was also elevated by corticosterone, and a nondipping BP profile was induced. Hydrochlorothiazide restored rhythmicity of BP in corticosterone-treated mice without affecting BP in controls. Glucocorticoids influence the day:night variation in NCC activity via kinases that control phosphorylation. Abnormal glucocorticoid rhythms impair NCC and induce nondipping. Night-time dosing of thiazides may be particularly beneficial in patients with modest glucocorticoid excess.

Chronotherapy with conventional blood pressure medications improves management of hypertension and reduces cardiovascular and stroke risks

Correlation between blood pressure (BP) and target organ damage, vascular risk and long-term patient prognosis is greater for measurements derived from around-the-clock ambulatory BP monitoring than in-clinic daytime ones. Numerous studies consistently substantiate the asleep BP mean is both an independent and a much better predictor of cardiovascular disease (CVD) risk than either the awake or 24 h means. Sleep-time hypertension is much more prevalent than suspected, not only in patients with sleep disorders, but also among those who are elderly or have type 2 diabetes, chronic kidney disease or resistant hypertension. Hence, cost-effective adequate control of sleep-time BP is of marked clinical relevance. Ingestion time, according to circadian rhythms, of hypertension medications of six different classes and their combinations significantly affects BP control, particularly sleep-time BP, and adverse effects. For example, because the high-amplitude circadian rhythm of the renin-angiotensin-aldosterone system activates during nighttime sleep, bedtime vs. morning ingestion of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers better reduces the asleep BP mean, with additional benefit, independent of medication terminal half-life, of converting the 24 h BP profile into more normal dipper patterning. The MAPEC (Monitorización Ambulatoria para Predicción de Eventos Cardiovasculares) study, first prospective randomized treatment-time investigation designed to test the worthiness of bedtime chronotherapy with ⩾1 conventional hypertension medications so as to specifically target attenuation of asleep BP, demonstrated, relative to conventional morning therapy, 61% reduction of total CVD events and 67% decrease of major CVD events, that is, CVD death, myocardial infarction, and ischemic and hemorrhagic stroke. The MAPEC study, along with other earlier conducted less refined trials, documents the asleep BP mean is the most significant prognostic marker of CVD morbidity and mortality; moreover, it substantiates attenuation of the asleep BP mean by a bedtime hypertension treatment strategy entailing the entire daily dose of ⩾1 hypertension medications significantly reduces CVD risk in both general and more vulnerable hypertensive patients, that is, those diagnosed with chronic kidney disease, diabetes and resistant hypertension.

Opening the Debate: How to Fulfill the Need for Physicians' Training in Circadian-Related Topics in a Full Medical School Curriculum

BACKGROUND

Circadian rhythms are daily changes in our physiology and behavior that are manifested as patterns of brain wave activity, periodic hormone production, recurring cell regeneration, and other oscillatory biological activities. Their importance to human health is becoming apparent; they are deranged by shift work and jet-lag and in disparate conditions such as insomnia, sleep syndromes, coronary heart attacks, and depression, and are endogenous factors that contribute to cancer development and progression.

DISCUSSION

As evidence of the circadian connection to human health has grown, so has the number of Americans experiencing disruption of circadian rhythms due to the demands of an industrialized society. Today, there is a growing work force that experiences night shift work and time-zone shifts shaping the demands on physicians to best meet the needs of patients exposed to chronic circadian disruptions. The diverse range of illness associated with altered rhythms suggests that physicians in various fields will see its impact in their patients. However, medical education, with an already full curriculum, struggles to address this issue.

SUMMARY

Here, we emphasize the need for incorporating the topic of circadian rhythms in the medical curriculum and propose strategies to accomplish this goal.

Investigation on cardiovascular risk prediction using physiological parameters

Cardiovascular disease (CVD) is the leading cause of death worldwide. Early prediction of CVD is urgently important for timely prevention and treatment. Incorporation or modification of new risk factors that have an additional independent prognostic value of existing prediction models is widely used for improving the performance of the prediction models. This paper is to investigate the physiological parameters that are used as risk factors for the prediction of cardiovascular events, as well as summarizing the current status on the medical devices for physiological tests and discuss the potential implications for promoting CVD prevention and treatment in the future. The results show that measures extracted from blood pressure, electrocardiogram, arterial stiffness, ankle-brachial blood pressure index (ABI), and blood glucose carry valuable information for the prediction of both long-term and near-term cardiovascular risk. However, the predictive values should be further validated by more comprehensive measures. Meanwhile, advancing unobtrusive technologies and wireless communication technologies allow on-site detection of the physiological information remotely in an out-of-hospital setting in real-time. In addition with computer modeling technologies and information fusion. It may allow for personalized, quantitative, and real-time assessment of sudden CVD events.

Circadian rhythms and medical diseases: does it matter when drugs are taken?

BACKGROUND

Chronobiology is devoted to the study of biological rhythms. It is possible that a given medication may be therapeutic and safe when administered at some time, but subtherapeutic or poorly tolerated at another.

METHODS

We focused on some classes of drugs, widely used by the internists, performing a PubMed search with the single drugs associated with the MeSH terms "Chronotherapy", "Circadian rhythm", and "Chronobiology, phenomena". Among the studies found, we considered only those provided with discrete numerosity or clearly stated methodological characteristics.

RESULTS

The results of available studies were given, along with a series of short take-home messages at the end of each mini-chapter devoted to: antihypertensives, statins, anticoagulants, analgesics, drugs for acid-related disorders, and anti-asthmatic drugs. In particular, evidence of morning vs. evening administration, when applicable, was given for each medication.

CONCLUSIONS

Adequate evidence seems to support that at least ACE-inhibitors or angiotensin receptor blockers, simvastatin, corticosteroids (slow-release formulation) for arthritic patients, and ranitidine should preferably be administered in the evening. Morning dosing could be better for proton pump inhibitors, whereas time of administration is not crucial for asthma inhalation drugs. Studies are available for other drugs, but not so strong enough to draw definite conclusions. For now, we need prospective intervention trials specifically designed to investigate the long-term effects of a temporal approach to medical therapy. However, since switching to morning-evening administration or vice versa is simple and inexpensive, in some cases it could be considered, remembering that, in any case, adherence remains the crucial point.

Chronotherapy improves blood pressure control and reduces vascular risk in CKD

In patients with chronic kidney disease (CKD), the prevalence of increased blood pressure during sleep and blunted sleep-time-relative blood pressure decline (a nondipper pattern) is very high and increases substantially with disease severity. Elevated blood pressure during sleep is the major criterion for the diagnoses of hypertension and inadequate therapeutic ambulatory blood pressure control in these patients. Substantial, clinically meaningful ingestion-time-dependent differences in the safety, efficacy, duration of action and/or effects on the 24 h blood pressure pattern of six different classes of hypertension medications and their combinations have been substantiated. For example, bedtime ingestion of angiotensin-converting-enzyme inhibitors and angiotensin-receptor blockers is more effective than morning ingestion in reducing blood pressure during sleep and converting the 24 h blood pressure profile into a dipper pattern. We have identified a progressive reduction in blood pressure during sleep--a novel therapeutic target best achieved by ingestion of one or more hypertension medications at bedtime--as the most significant predictor of decreased cardiovascular risk in patients with and without CKD. Recent findings suggest that in patients with CKD, ambulatory blood pressure monitoring should be used for the diagnosis of hypertension and assessment of cardiovascular disease risk, and that therapeutic strategies given at bedtime rather than on awakening are preferable for the management of hypertension.

Timing is important in medication administration: a timely review of chronotherapy research

BACKGROUND

Chronotherapy involves altering the timing of medication administration to improve the overall control of a disease and to minimise treatment side-effects, and is an emerging concept in the field of therapeutics.

AIM

The aim of this review is to conduct an in-depth analysis of the recent literature in order to identify and evaluate the evidence base for drug chronotherapy.

METHOD

A literature search was conducted in three databases (Medline, Embase, International Pharmaceutical Abstracts) using the search terms "Chronotherapy", "Chronopharmacology", "Chronopharmacokinetics", "Chronopharmacodynamics", "Chronoefficacy", "Chronoformulation", "Morning and Evening", "Morning and Bedtime" and their combinations. The selection criteria for the inclusion of articles in the review included currency (years 2008-Aug 2011), publication in English language, studies done in Humans and non-review articles that pertained to 'drug' therapy.

RESULTS

Our search revealed a total of 192 journal articles, of which 41 articles were selected for review. The specific hypothesis for the effectiveness of chronotherapy that was tested in these 41 studies was chronoeffectiveness (n = 34), followed by chronopharmacokinetics (n = 5), chronomodulation (n = 3) and chronopharmacodynamics (n = 2). The findings from two-thirds (n = 27) of the reviewed studies, support the notion of chronotherapy.

CONCLUSION

The review presents the scope of chronotherapy in drug utilization. We believe that the knowledge of chronotherapy is growing and the current research for chronotherapy is promisingly in the conceptualization or early experimental phase. Going forward, chronotherapy studies should also explore genetic, gender and age related differences. Preliminary screening of new drugs for chronotherapeutic potential may be a way of enhancing quality use of medicines.

Administration-time differences in effects of hypertension medications on ambulatory blood pressure regulation

Specific features of the 24-h blood pressure (BP) pattern are linked to progressive injury of target tissues and risk of cardiovascular disease (CVD) events. Several studies have consistently shown an association between blunted asleep BP decline and risk of fatal and nonfatal CVD events. Thus, there is growing focus on ways to properly control BP during nighttime sleep as well as during daytime activity. One strategy, termed chronotherapy, entails the timing of hypertension medications to endogenous circadian rhythm determinants of the 24-h BP pattern. Significant and clinically meaningful treatment-time differences in the beneficial and/or adverse effects of at least six different classes of hypertension medications, and their combinations, are now known. Generally, calcium channel blockers (CCBs) are more effective with bedtime than morning dosing, and for dihydropyridine derivatives bedtime dosing significantly reduces risk of peripheral edema. The renin-angiotensin-aldosterone system is highly circadian rhythmic and activates during nighttime sleep. Accordingly, evening/bedtime ingestion of the angiotensin-converting enzyme inhibitors (ACEIs) benazepril, captopril, enalapril, lisinopril, perindopril, quinapril, ramipril, spirapril, trandolapril, and zofenopril exerts more marked effect on the asleep than awake systolic (SBP) and diastolic (DBP) BP means. Likewise, the bedtime, in comparison with morning, ingestion schedule of the angiotensin-II receptor blockers (ARBs irbesartan, olmesartan, telmisartan, and valsartan exerts greater therapeutic effect on asleep BP, plus significant increase in the sleep-time relative BP decline, with the additional benefit, independent of drug terminal half-life, of converting the 24-h BP profile into a more normal dipping pattern. This is the case also for the bedtime versus upon-awakening regimen of combination ARB-CCB, ACEI-CCB, and ARB-diuretic medications. The chronotherapy of conventional hypertension medications constitutes a new and cost-effective strategy for enhancing the control of daytime and nighttime SBP and DBP levels, normalizing the dipping status of their 24-h patterning, and potentially reducing the risk of CVD events and end-organ injury, for example, of the blood vessels and tissues of the heart, brain, kidney, and retina.