Abstract
The present paper reviews the importance of the time of day in medicine, with a special emphasis on infectious diseases and antibiotics. Data were obtained from scientific journals following a literature search and from studies carried out in the authors’ laboratory. Data indicating that the signs and symptoms of disease do not appear at random over a 24 h period are now available. For example. asthma occurs usually at night, while myocardial infarction or anginal attacks occur in the early morning hours. Very little data are available on infectious diseases, and most studies were carried out on the pharmacokinetics and toxicity of antibiotics. These data suggest that antimicrobial agents are eliminated more rapidly when injected during the activity period of animals or humans. It is also noteworthy that aminoglycosides and amphotericin B induced less toxicity during the activity period of laboratory animals or patients, and highest toxicity occurred during the sleeping period. This is particularly evident with data on aminoglycosides. Temporal variations were also observed in the effectiveness of aminoglycosides, but these data were found only in animal models of infectious diseases. Temporal variations in the pharmacokinetics, toxicity and effectiveness of a ntibiotics may lead to a more rational use of medications in patients.