title: Tricyclic antidepressants for chronic low-back pain. Mechanisms of action and predictors of response.
abstract: Patients with chronic low-back pain and depression were treated double blind with desipramine or doxepin. During this treatment several hypotheses regarding the modes of action of these drugs were examined. A low serotonin hypothesis was supported by the fact that patients who had pain relief following an acute challenge with fenfluramine, a relatively pure releaser of serotonin, were significantly more likely to have pain relief on either antidepressant. The antidepressants did not change cerebrospinal fluid (CSF) beta-endorphin levels, acute pain tolerance, or electromyogram (EMG) levels. The nonsedating antidepressant desipramine was as effective as doxepin; 60% of patients had significant pain relief. Pain relief was associated with depression relief, but several patients had only pain or depression relief. Patients who had a substantial physical basis for their pain responded as well as those who did not.
mesh_terms: D000328:Adult; D001416:Back Pain / Q000150:complications / Q000188:drug therapy*; D002908:Chronic Disease; D002986:Clinical Trials as Topic; D003866:Depressive Disorder / Q000150:complications / Q000188:drug therapy; D003891:Desipramine / Q000627:therapeutic use*; D004311:Double-Blind Method; D004316:Doxepin / Q000627:therapeutic use*; D004359:Drug Therapy, Combination; D005260:Female; D005277:Fenfluramine / Q000627:therapeutic use; D006801:Humans; D008297:Male; D011897:Random Allocation
chemical_list: D004316:Doxepin; D005277:Fenfluramine; D003891:Desipramine