The need to take increasingly higher doses of a drug to obtain the same physical or mental effect.
Tolerance develops after taking a drug over a period of time and usually results either from the liver becoming more efficient at breaking the drug down or from body tissues becoming less sensitive to it.
This occurs when the response to a particular amount of a drug or physiological messenger decreases, so that a larger dose must be given to produce the same response as before. It is particularly common with certain drug dependencies (see DEPENDENCE): for example, with MORPHINE or HEROIN.
n. the reduction or loss of the normal response to a drug or other substance that usually provokes a reaction in the body. Drug tolerance 1. may develop after taking a particular drug over a long period of time. In such cases increased doses are necessary to produce the desired effect. Some drugs that cause tolerance also cause *dependence. See also glucose tolerance test; immunological tolerance; tachyphylaxis. 2. acceptance of others whose beliefs, customs, behaviour, or lifestyle are different from one’s own or from accepted social norms. Tolerance is an indispensable virtue in all medical staff and may be of clinical importance when a patient displays unusual behaviour during initial assessment.
A way of assessing the body’s e?ciency at metabolising GLUCOSE. The test is used in the diagnosis of DIABETES MELLITUS. The patient is starved for up to 16 hours, after which he or she is fed glucose by mouth. The concentrations of glucose in the blood and urine are then measured at half-hour intervals over a period of two hours.... glucose-tolerance test
a failure of the body to distinguish between materials that are ‘self’, and therefore to be tolerated, and those that are ‘not self’, against which it mounts an *immune response. Tolerance results from the interaction of antigens with lymphocytes under conditions in which the lymphocytes are not activated but rendered unresponsive.... immunological tolerance
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