What is Tolerance ?.
In drugs abuse Tolerance is defined as the need to increase the dose progressively in order to produce the effect originally achieved by smaller amounts.
As Tolerance is a progressive increase in dosage, it may be several hundred fold greater than the first dose after a short period of time.
In addiction to drugs, alcohol and other substances is common to find tolerance and physical or psychological dependence. The elimination of such drugs or alcohol triggers a withdrawal syndrome. For example, we will find physical dependence, tolerance and withdrawal in heroin addiction.
(Edited by Dra Moya Guirao)