Definition: Tolerance is a term that refers to the decreasing effectiveness of a medication over time. An example might be if your pain goes away the first time you take one painkiller, but after a few weeks, you need to add another one in order to get the same benefit.
Patients may develop tolerance to any of the effects a drug may have, including side effects. For patients and their doctors, a main concern is the length of time before the analgesic -- or pain killing -- benefits are no longer experienced. Tolerance also varies according to type of pain, along with other individual factors.
According to the American Chronic Pain Association, tolerance is not the same as an addiction.
Also Known As: becoming immune to a drug
Examples:
As tolerance builds up, more pills are required for the patient to receive previous levels of pain relief.
