[Circadian rhythms and clinical pharmacology]

Discoveries of rhythms in human biological functions: a historical review

Though there are very early and ancient observations on the daily variation in physiological and pathophysiological functions (e.g., bronchial asthma), more detailed and scientific reports were not published until the beginning of the 17th century. The aim of this review is to bring those reports to the attention of researchers of chronobiology and chronopharmacology. The ancient books and their contents, which constitute the basis for this review, are part of the personal library collection of the author; numerous observations and reports on biologic rhythms in man are presented here for the first time. The intent of this review is to demonstrate that the fields of chronobiology and chronopharmacology are not only a new and modern branch of science, but that it stands on the shoulders of wonderful and insightful observations and explanations made by our scientific forefathers. It is the hope that the reader will enjoy the richness of the ancient reports that contribute to our present knowledge achieved through astute early biologic rhythm research.

Chronopharmacology and controlled drug release

Circadian rhythms in the body are well established and are an important factor to consider when administering drugs. Many diseases display symptoms and onset characteristics that are not randomly distributed within 24 h (e.g., coronary infarction, angina pectoris, asthmatic attacks and peptic ulcer perforations); therefore, it is not surprising that the effects and/or pharmacokinetics of drugs can display significant daily variations. Recent data, primarily concerned with the chronopharmacokinetics of antiasthmatics, histamine H2-blockers and cardiovascular active drugs (e.g., propanolol, organic nitrate and nifedipine) are described as representative examples in this review. The data demonstrate that biological rhythms should have been taken into account when evaluating drug delivery systems, galenic formulations and pharmacokinetics as a basis for drug treatment.