Amitriptyline is a tricyclic antidepressant agent which also has
analgesic properties. Whether its analgesic effects are linked
to its mood-altering activity or attributable to a discrete
pharmacological action (or a combination of both) is unknown.
Clinical trials demonstrate that oral amitriptyline achieves
at least a good or moderate response in up to two-thirds of
patients with post-herpetic neuralgia and three-quarters of
patients with painful diabetic neuropathy, neurogenic pain
syndromes that are often unresponsive to narcotic analgesics.
Amitriptyline has also demonstrated efficacy in heterogeneous
groups of patients with chronic non-malignant pain.
possible areas of use for amitriptyline are in patients with
fibromyalgia or as an adjuvant for uncontrolled cancer pain,
although evidence for the latter application is limited.
Adverse events resulting from the antimuscarinic activity of
amitriptyline (primarily dry mouth and sedation) are commonly
reported, even at the low dosages used for the control of
pain. Low starting doses and careful dosage titration may
help to minimise these effects. Orthostatic hypotension and
tachycardia, sometimes associated with tricyclic
antidepressant agents, may also pose a problem in the elderly.
In summary, amitriptyline has a valuable place in the
treatment of chronic pain conditions that affect the elderly
provided that the drug is used judiciously to minimise
adverse effects. Importantly, amitriptyline remains the best
studied of the antidepressant agents in post-herpetic
neuralgia and diabetic neuropathy and is an important and
effective treatment option in these syndromes.