Fibromyalgia was initially thought to be a musculoskeletal disorder. Research now suggests it’s a disorder of the central nervous system — the brain and spinal cord. Researchers believe that fibromyalgia amplifies painful sensations by affecting the level and activity of brain chemicals responsible for processing pain signals.

Now researchers claim that combining pregabalin, an anti-seizure drug, with duloxetine, an antidepressant, can safely improve outcomes in fibromyalgia, including not only pain relief, but also physical function and overall quality of life. Until now, these drugs have been proven, individually, to treat fibromyalgia pain.

“Previous evidence supports added benefits with some drug combinations in fibromyalgia,” researchers say. “We are very excited to present the first evidence demonstrating superiority of a duloxetine-pregabalin combination over either drug alone.”

This trial compares a pregabalin-duloxetine combination to each monotherapy. Using a randomized, double-blind, 4-period crossover design, participants received maximally tolerated doses of placebo, pregabalin, duloxetine, and pregabalin-duloxetine combination-for 6 weeks.

Primary outcome was measured by daily pain (0-10); secondary outcomes included global pain relief, Fibromyalgia Impact Questionnaire, SF-36 survey, Medical Outcomes Study Sleep Scale, Beck Depression Inventory (BDI-II), adverse events, and other measures.

Based upon these measures, the evidence showed that combining pregabalin and duloxetine for fibromyalgia improves multiple clinical outcomes vs monotherapy.

This study is the latest in a series of clinical trials — funded by the Canadian Institutes of Health Research (CIHR) — that Dr. have been conducted on combination therapies for chronic pain conditions. By identifying and studying promising drug combinations, research is showing how physicians can make the best use of current treatments available to patients.

“The value of such combination approaches is they typically involve drugs that have been extensively studied and are well known to health-care providers,” says Queen’s University researcher Dr. Ian Gilron.

This new research was published in the journal Pain.