Utilization and mechanism of action of tricyclic antidepressants in the treatment of chronic facial pain: a review of the literature.

Tricyclic antidepressants show promise in the treatment of chronic facial pain. The antinociceptive activity of this class of drugs appears to be independent of any antidepressant effects. An hypothesis is proposed that tricyclics antidepressants activate a descending serotonergic (5-HT1) antinociceptive pathway which in turn influences endogenous opioids. This antinociceptive pathway appears to utilize an endogenous pain modulation system. Future studies may demonstrate the operative mechanisms of action and open understanding as to etiologic factors.