Tricyclic antidepressants in the treatment of cancer pain: a review.

The role of tricyclic antidepressants (TCAs) in the treatment of cancer pain is of growing interest. Various studies, all but one of them open, have suggested that TCAs are effective and safe in the treatment of pain caused by different types of cancer. The mechanisms of action by which TCAs decrease the pain perception are not fully clear. However, there are two main hypotheses. The first suggests that the drugs act primarily on the emotional component of pain, thus breaking the vicious circle of the perception of pain; the second suggests that the TCAs themselves have a specific analgesic action linked to a direct activity on the structures of the CNS. Further clinical studies, and in particular double-blind studies, are clearly necessary to provide more convincing and definitive results.