Circadian rhythms are driven and maintained by circadian clock gene networks in both brain and peripheral organs. In the liver, circadian rhythms produce oscillation in drug Phase-I, Phase-II, and Phase-III (transporters) metabolism genes, which in turn would affect drug disposition and detoxication, resulting in diurnal variations of efficacy and toxicity when drugs are given at different times of the day. On the other hand, drugs and toxicants could affect circadian clock gene expression to produce biological effects leading to therapeutic or toxic outcomes. This chapter reviewed the relevant literature and a dozen of publications from our work, discussed the interactions of circadian clock genes with drugs and/or toxicants to better understand the importance of circadian clock gene expression as novel targets in Pharmacology and Toxicology.
Part of the book: Circadian Rhythm