In combination the two drugs also reduce pain more consistently than when either of the drugs is administered alone, reports lead researcher Dr. Ian Gilron, Director of Clinical Pain Research for Queen's Departments of Anesthesiology, and Pharmacology & Toxicology.
"This is exciting because there aren't many non-opioid treatments available to complement morphine in relieving movement-related pain," Dr. Gilron says.
Results of the study are published on-line in the January 2005 issue of PAIN, the official journal of the International Association for the Study of Pain. Also on the team from Queen's are Elizabeth Orr and Jorge Zamora (Anesthesiology), Dongsheng Tu (Mathematics and Statistics), and Peter O'Neill (Obstetrics and Gynecology); and from the University of Toronto Faculty of Medicine, Allan Bell.
One of the biggest issues for post-operative recovery from abdominal or chest surgery is that people tend to lie still and take shallow breaths to avoid pain. As a result, their lungs don't re-expand quickly enough after the partial lung collapse that occurs during the operation.
While morphine works well at reducing pain when patients are at rest, it is not as effective during movement or when the patient takes a deep breath or coughs, explains Dr. Gilron. An epidural with local anesthetic that partially numbs the nerves to the affected site will prevent the pain caused by deep breaths or coughing, and allow the lungs to recover better. Epidurals are currently the best pain treatment option after many major surgeries. However, this is a fairly invasive procedure, which has some risk and also requires more medical resources.
"We continue to search for new app