Chronopharmacology: a therapeutic frontier.

Chronopharmacology, the study of time-dependent physiological response to drugs, and its relationship to current drug therapy are discussed. The objective of chronotherapy is to apply chronobiologic principles to the treatment of human disease. The appropriate patients for chronotherapy are those who are receiving high-risk drugs, who have a high-risk disease (e.g., cancer) or who are receiving a high-cost drug. Although little is known of the chronobiologic characteristics of many drugs or diseases, researchers should take into account the possible relationship of chronobiology to drug effects when designing therapeutic trials. Drug therapy can be optimized by tailoring dosing schedules and distribution systems to chronobiologic patterns.