Progressive diminution of the susceptibility of a human or animal to the effects of a drug, resulting from its continued administration. It should be differentiated from drug resistance where in an organism, disease, or tissue fails to respond to the intended effectiveness of a chemical or drug. It should also be differentiated from maximum tolerated dose and no-observed-adverse-effect level.
Repeated use of some substance or drug, often narcotics, so that larger and larger doses are required to produce the same physiologic and/or psychological effect obtained previously by a smaller dose.
A condition in which greater and greater amounts of a drug are needed to be effective.
A condition in which a drug has been given to someone for so long that his or her body no longer reacts to it, and the dosage has to be increased.
The progressive decrease in the effectiveness of a drug.
A condition in which a user needs more of a drug to get the same effect.