Studies support clinical use of antidepressants for treatment of postoperative pain

Antidepressants are known to provide effective pain relief for various chronic pain conditions; however, the jury is still out on their use in treating the millions of patients who suffer from acute or chronic pain following surgery. A first-of-its-kind literature review published in the September issue of Anesthesiology, the official medical journal of the American Society of Anesthesiologists® (ASA®), suggests although a majority of studies report positive outcomes, there is currently insufficient evidence to support the clinical use of antidepressants for the treatment of postoperative pain.

"There is a need for improved treatment options in the management of postoperative pain, and antidepressants could potentially be a valuable addition," said Ian Gilron, M.D., lead author, professor and director of clinical pain research at Queen's University in Ontario, Canada. "Our review of the literature showed several positive trial results, but we also found important research limitations in the studies, indicating a need for higher quality, more definitive trials on antidepressant use for postsurgical pain."

In the study, researchers performed a systematic review of all currently published clinical trials on antidepressants and postoperative pain. Fifteen studies on acute (985 patients) and three studies on chronic (565 patients) postoperative pain were included. Extracted data from the studies included pain at rest and with movement, pain relief, adverse effects and other outcomes (e.g. mood, sleep, physical function).

Nearly half of the studies (eight of the acute and one of the chronic pain) suggested that antidepressants resulted in significant treatment benefits over placebo. However, researchers identified several important limitations in many of the trials (e.g. too few patients, inadequate safety evaluation and procedure specificity, variable dosing, limited pain assessment, etc.) that indicated a need for additional studies.

According to the review, future clinical trials should optimize dosing, timing and duration of antidepressant treatment, trial size, patient selection, safety evaluation and reporting, procedure specificity, and assessment of movement-evoked pain relevant to postoperative functional recovery. Trials should also better define the risk-benefit ratio of antidepressants in postoperative pain management since these drugs can be associated with serious adverse effects in the time around surgery, the authors note.

More than 40 million surgical procedures are performed in North America alone each year and the majority of these are associated with moderate to severe acute pain in the days to weeks immediately following surgery. Additionally, a substantial proportion of surgical patients experience chronic postoperative pain many months or even years after their original surgery.