A. PALMA, P. PANCHERI - Vol. 10, March 2004, Issue 1
Testo Immagini Bibliografia Summary Indice
Terapia del dolore con farmaci antidepressivi
Focus sulla venlafaxina
Antidepressant drugs in the treatment of somatic pain
Focus on venlafaxine
Physical pain is widely diffused in various contexts of primary care and specialty medicine with a varying clinical expression as to criteria and intensity, with a duration and therapeutic response that basically depends on the nature of the triggering noxa.
Aims
This review aims at providing an overview of clinical studies that assessed the efficacy of antidepressant drugs in the treatment of pain symptoms so to define a possible therapeutic specificity profile. A further objective is to estrapolate data from literature regarding some indications on which to construct a psychobiological rationale that justifies and orients the choice of an antidepressant in the treatment of somatic pain on the basis of the exposed psychophysical problems, specifically, the single individual. We aim at investigate thoroughly whether neurotransmitter ambiguity, shared by anxiety and depressive disorders with the mechanisms of action which are at the basis of perception, peripheral and central transmission of pain justifies a therapeutic rationale to use antidepressants as regulators of pain threshold, although with a limited or complementary role. Finally, the therapeutic perspectives of venlafaxine, a 5-HT–NA selective antidepressant, are taken into consideration in the treatment of somatic symptoms and pain.
Results
Literature presents evidence for significant analgesic efficacy of antidepressants with a mainly 5-HT–NA receptor profile. Antidepressant drugs show a reduction and at times resolution of pain related to chronic, functional somatic disorders secondary to excessive muscular tension. Clinical evidence of studies controlled versus placebo describes an important modulation of pain threshold by some antidepressants, also with respect to disorders that comprise neuropathy secondary to diabetes, rheumatic disease, herpes virus infections. Data on efficacy of antidepressants in oncological pain are rather limited.
Conclusions
Studies considered in this review appear to confirm what has been described in animal experiments, i.e., the important influence of the noradrenergic and serotonergic system in perception and transmission of the nociceptive stimulus, thus supporting a therapeutic rationale for antidepressants in controlling pain of central and mixed central-peripheral origin, as well as on some aspects of nociceptive sensibility. Antidepressants with greater specificity for pain treatment seem to be represented by molecules with a mainly 5-HT/NA receptor profile and with a high therapeutic index considering previous polytherapies in the neuropathic patient or in the one presenting pain symptoms of different nature. However, further controlled studies are needed to assess in man the neurobiological mechanisms used by antidepressants on acute and chronic pain threshold. Several doubts remain on the role and neurophysiological relationships which link in man chronic stress with mood state and on possible modifications of pain threshold.