If Cymbalta (duloxetine) sounds familiar, it may be because it recently received FDA approval for the management of fibromyalgia. Now a new study indicates that taking 60 – 120 mg of duloxetine once daily may also be helpful in reducing chronic low back pain.
Duloxetine-treated patients reported a significantly greater reduction in pain scores than placebo-treated patients. Thirty-one percent of duloxetine-treated patients experienced a 50 percent reduction in pain, compared with 19 percent of placebo-treated patients, as measured by an 11-point Likert pain scale. Physicians consider a pain reduction of at least 30 percent as clinically significant.
Additional results from the study include:
- A significantly greater reduction in pain was recorded in the first week after starting the 60 mg daily dose and continued throughout the 13 weeks of the acute therapy phase of the study.
- Superiority to the placebo in most secondary analyses including weekly 24-hour average pain score, weekly 24-hour worst pain and weekly 24-hour night pain was observed.
- Superiority to the placebo was not observed in two items: pain interference with general activity and pain interference with sleep.
- Statistically significant differences in bodily pain, general health and vitality were observed.
- The duloxetine treatment group experienced a significantly greater improvement on the work-activity impairment score compared with the placebo treatment group.
More than five percent of patients in the duloxetine group discontinued the study because of adverse events. The most common adverse events reported were nausea, dry mouth, fatigue, diarrhea, excessive sweating, dizziness and constipation.
Another Cymbalta Study
It should be noted that a separate study on duloxetine for chronic low back pain was recently presented at the 12th World Congress of Pain in Glasgow, Scotland. In that study, duloxetine showed significant pain reductions compared with the placebo from week three through week 11 of the 13-week trial. However, it did not significantly differ from the placebo in the first and last two weeks of the study.
Given these results, I think additional studies are needed to determine whether duloxetine will be useful in reducing chronic low back pain on an ongoing basis.
How Cymbalta Works
Serotonin and norepinephrine in the brain and spinal cord are believed to both mediate core mood symptoms and help regulate the perception of pain. Based on preclinical studies, Cymbalta is a balanced and potent reuptake inhibitor of serotonin and norepinephrine that is believed to potentiate the activity of these chemicals in the central nervous system (brain and spinal cord). While the mechanism of action of Cymbalta is not fully known, scientists believe its effects on depression and anxiety symptoms, as well as its effect on pain perception, may be due to increasing the activity of serotonin and norepinephrine in the central nervous system.
Cymbalta is FDA approved to treat major depressive disorder and generalized anxiety disorder, and to manage diabetic peripheral neuropathic pain and fibromyalgia.
Published On: August 27, 2008