Tolerance to a drug to which an individual has not been exposed because tolerance had developed to another substance over a period of long-term administration. A person who has developed tolerance to alcohol will have a diminished response to the usual dose of a denzodiazepine medication because tolerance to alcohol also has induced tolerance to the benzodiazepine’s effect.
A condition in which tolerance to one drug results in a lessened pharmacological response to another drug of the same class even though the person never used this drug before.
Resistance to the effects of a drug that develops through the repeated use of another, similar drug. Usually cross-tolerance arises with drugs that are chemically similar and have similar effects. For example, a person tolerant to heroin is usually tolerant to morphine and methadone as well.
The development of tolerance to all the medications within a particular class of agents rather than simply to one agent.