EXCRETION OF DRUGS
Despite the reduction in activity that occurs as a drug leaves its site of action, it may remain in the body for a considerable period, especially if it is strongly bound to tissue components. Thus, reduction in pharmacological activity and drug elimination are to be seen as related but separate phenomena.
Excretion, along with metabolism and tissue redis-tribution, is important in determining both the duration of drug action and the rate of drug elimination. Excretion is a process whereby drugs are transferred from the internal to the external environment, and the principal organs involved in this activity are the kid-neys, lungs, biliary system, and intestines.