Clinical chronopharmacology of the cardiovascular system: hypertension and coronary heart disease.

There is sound evidence that the cardiovascular and the renal systems are well organized in time. Mechanisms of regulation and pathophysiological events are not evenly distributed over the 24-h scale. Moreover, certain diseases may even alter the physiological circadian pattern both in the cardiovascular system and in the kidneys. This observation bares implications for drug treatment, e.g., regarding drug formulations and dosing time intervals. Pitfalls may arise from neglecting circadian phase-dependency in pharmacokinetics and in the concentration-effect relationship. Moreover, different types of drugs may be superior to others when circadian time-related symptoms are concerned. No doubt, "time-of-day" has to be included in our diagnostic and therapeutic strategies.