Abstract
Previous studies showing circadian variation in pharmacologic response to drugs in man and experimental animals have been reviewed. The chronobiologic response is discussed in terms of the pharmacologic factors that determine drug action. The importance of internal markers in chronopharmacologic studies is emphasized and is illustrated by our studies with the antihypersive drugs. Identification of chronobiologic variations in the therapeutic and toxic response to drugs, when present, along with an understanding of their mechanisms, would permit the design of optimal therapeutic regimens for these drugs.
