Tolerability refers to the degree to which overt
adverse effects of a drug can be tolerated by a patient.
Tolerability of a particular drug can be discussed in a general sense, or it can be a quantifiable measurement as part of a clinical study. Usually, it is measured by the rate of "dropouts", or patients that forfeit participation in a study due to extreme adverse effects. Tolerability, however, is often relative to the severity of the medical condition a drug is designed to treat.
For instance, cancer patients may tolerate significant pain or discomfort during a chemotherapeutic study with the hope of prolonging survival or finding a cure, whereas patients experiencing a benign condition, such as a headache, are less likely to.
As an example,
tricyclic antidepressant
Tricyclic antidepressants (TCAs) are a class of medications that are used primarily as antidepressants, which is important for the management of depression. They are second-line drugs next to SSRIs. TCAs were discovered in the early 1950s and we ...
s (TCAs) are very poorly tolerated and often produce severe side effects including
sedation
Sedation is the reduction of irritability or agitation by administration of sedative drugs, generally to facilitate a medical procedure or diagnostic procedure. Examples of drugs which can be used for sedation include isoflurane, diethyl ether, ...
,
orthostatic hypotension, and
anticholinergic effects, whereas newer antidepressants have far fewer adverse effects and are well tolerated.
Drug tolerability should not be confused with
drug tolerance, which refers to subjects' reduced reaction to a drug following its repeated use.
See also
*
Side effect
References
Clinical pharmacology
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