出典:Wikipedia
出典:『Wikipedia』 (2011/07/07 22:39 UTC 版)
Physiological tolerance or drug tolerance is commonly encountered in pharmacology, when a subject's reaction to a drug (such as an opiate painkiller, benzodiazepine or other psychotropic drug) is reduced at a later time even though the dose or concentration at the effect site is the same. This means that larger doses are required to achieve the same effect. Drug tolerance can involve both psychological drug tolerance and physiological factors. Characteristics of drug tolerance: it is reversible, the rate depends on the particular drug, dosage and frequency of use, differential development occurs for different effects of the same drug. Physiological tolerance also occurs when an organism builds up a resistance to the effects of a substance after repeated exposure. This can occur with environmental substances, such as salt or pesticides.