Chronopharmacology of cardiovascular therapy

Chronopharmacodynamics of drugs in toxicological aspects: A short review for clinical pharmacists and pharmacy practitioners

For many decades, researchers are aware of the importance of circadian rhythm in physiological/biochemical properties and drug metabolism. Chronopharmacology is the study of how the effects of drugs vary with biological timing and endogenous periodicities. It has been attaching substantial attention in the last years. Chronopharmacodynamics mainly deals with the biochemical and physiological effects of drugs on the body, the mechanisms of drug action, the relationship between drug concentration and effect in relation to circadian clock. In this review, we will focus on mammalian circadian pharmacodynamics and discuss new chronotherapy approaches. Moreover, we will try to highlight the chronopharmacodynamics of cardiovascular drugs, anti-cancer drugs, analgesics and non-steroidal anti-inflammatory drugs (NSAIDs) and give some practical concerns for clinical pharmacists and pharmacy practitioners, concerning this issue.

The effect of continuous nursing intervention guided by chronotherapeutics on ambulatory blood pressure of older hypertensive patients in the community

AIMS AND OBJECTIVES

To explore the effect of continuous nursing intervention guided by chronotherapeutics so as to provide the easy, noninvasive, effective and acceptable intervention for older hypertensive patients in the community.

BACKGROUND

Many researchers studied the effect of administration at different times on blood pressure control and circadian rhythm. However, the individual administrative time was set ambiguously in previous studies.

DESIGN

A semi-experimental study.

METHODS

In the study, 90 eligible patients were recruited and separated into three groups randomly, which were the control group, intervention group A (behaviour and chronotherapy intervention) and intervention group B (behaviour intervention). At 6 and 12 months after the study, the intervention groups were measured 24-hour ambulatory blood pressure monitoring.

RESULTS

There were significant differences in ambulatory blood pressure monitoring parameters of the two intervention groups at different measurement times, and there were interaction between measurement time and different groups. The number of patients with dipper increased and reverse dipper decreased in group A as the intervention applied. There were statistical differences between two groups. The number of patients with morning surge in group A decreased more, and there were statistical differences between two groups at six months after the intervention.

CONCLUSIONS

The behaviour and chronotherapy intervention based on the patients' ambulatory blood pressure monitoring can control casual blood pressure much better and last longer, which can also improve patients' indexes of ambulatory blood pressure monitoring better than behaviour intervention only. The behaviour and chronotherapy intervention can increase patients' nocturnal blood pressure drop, increase the number of patients with dipper and decrease reverse dipper, and improve blood pressure surge in the morning.

RELEVANCE TO CLINICAL PRACTICE

Nurses can use continuous nursing intervention guided by chronotherapeutics to help improve hypertension of older patients better in the community.

Influences of the circadian clock on neuronal susceptibility to excitotoxicity

Stroke is the third leading cause of death and the primary cause of morbidity in the United States, thus posing an enormous burden on the healthcare system. The factors that determine the risk of an individual toward precipitation of an ischemic event possess a strong circadian component as does the ischemic event itself. This predictability provided a window of opportunity toward the development of chronopharmaceuticals which provided much better clinical outcomes. Experiments from our lab showed for the first time that neuronal susceptibility to ischemic events follows a circadian pattern; hippocampal neurons being most susceptible to an ischemic insult occurring during peak activity in a rodent model of global cerebral ischemia. We also demonstrated that the SCN2.2 cells (like their in vivo counterpart) are resistant to excitotoxicity by glutamate and that this was dependent on activation of ERK signaling. We are currently working on elucidating the complete neuroprotective pathway that provides a barricade against glutamate toxicity in the SCN2.2 cells. Our future experiments will be engaged in hijacking the neuroprotective mechanism in the SCN2.2 cells and applying it to glutamate-susceptible entities in an effort to prevent their death in the presence of excitotoxicity. Despite the advancement in chronopharmaceuticals, optimal clinical outcome with minimal adverse events are difficult to come by at an affordable price. Superior treatment options require a better understanding of molecular mechanisms that define the disease, including the role of the circadian clock.

Circadian variations in blood pressure : implications for chronotherapeutics

The management of hypertensive patients usually ignores or gives little credit to the biologic rhythms inherent to the disease process and their potential clinical implications. The development of ambulatory blood pressure monitoring and the rapidly growing popularity of home blood pressure measurements by patients have now generated a series of new clinical questions that are directly linked to the chronobiology of the cardiovascular system, such as the clinical interpretation of a blunted nocturnal fall in blood pressure or the difficulty of achieving adequate blood pressure control in the morning. Today, there is growing evidence that night-time blood pressure, and particularly the absence of a decrease in sleep blood pressure, contributes to the occurrence of target organ damages, and that the early morning rise in blood pressure increases the risk of developing cardiovascular events, including stroke, perhaps independently of 24-hour blood pressure levels. On the basis of these observations, it may be necessary to reconsider the way antihypertensive drugs are prescribed in order to obtain smooth, 24-hour blood pressure control, respecting the circadian pattern of blood pressure. Several approaches exist, including the use of drugs that lower blood pressure around the clock and respect the diurnal rhythm. Preliminary studies performed with such agents have provided interesting results. However, there is a clear need for large clinical trials demonstrating the clinical superiority of this approach. In any case, a better understanding of the importance of the circadian variations of blood pressure could certainly have a major impact on our view of the therapeutic management of hypertensive patients.

Chronopharmaceutics: gimmick or clinically relevant approach to drug delivery?

Due to advances in chronobiology, chronopharmacology, and global market constraints, the traditional goal of pharmaceutics (e.g. design drug delivery systems with a constant drug release rate) is becoming obsolete. However, the major bottleneck in the development of drug delivery systems that match the circadian rhythm (chronopharmaceutical drug delivery systems: ChrDDS) may be the availability of appropriate technology. The last decade has witnessed the emergence of ChrDDS against several diseases. The increasing research interest surrounding ChrDDS may lead to the creation of a new sub-discipline in pharmaceutics known as chronopharmaceutics. This review introduces the concept of chronopharmaceutics, addresses theoretical/formal approaches to this sub-discipline, underscores potential disease-targets, revisits existing technologies and examples of ChrDDS. Future development in chronopharmaceutics may be made at the interface of other emerging disciplines such as system biology and nanomedicine. Such novel and more biological approaches to drug delivery may lead to safer and more efficient disease therapy in the future.