In pharmacology, 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 antidepressants (TCAs) are very poorly tolerated and often produce severe side effects including
sedation,
orthostatic hypotension, and
anticholinergic
Anticholinergics (anticholinergic agents) are substances that block the action of the acetylcholine (ACh) neurotransmitter at synapses in the central nervous system, central and peripheral nervous system.
These agents inhibit the parasympatheti ...
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
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Side effect
In medicine, a side effect is an effect of the use of a medicinal drug or other treatment, usually adverse but sometimes beneficial, that is unintended. Herbal and traditional medicines also have side effects.
A drug or procedure usually use ...
References
Clinical pharmacology
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