[Chronopharmacology--importance of the biological clock in drug treatment].

Nearly all functions of living creatures including man exhibit significant daily variations. Today, internal biological clocks are traced down to the molecular level. In man pathophysiological events such as coronary infarction, angina pectoris, asthma attacks and gastro-intestinal ulcers do not occur at random but exhibit a clear-cut daily rhythmic pattern. It is, therefore, not surprising that the pharmacokinetics as well the effects and side-effects of drugs can vary significantly with the time of day as has been documented in many clinical studies. Thus, "time-of-day" has to be regarded as an important factor to evaluate drug efficacy and its therapeutic window.