Muscle Relaxant May Ease Fibromyalgia Pain
Low Doses of Cyclobenzaprine Improved Sleep, Pain in Small Study
Sept. 14, 2011 -- Low doses of the muscle relaxant cyclobenzaprine, taken at bedtime, help people with fibromyalgia sleep better and feel less pain, according to a small study.
"Bedtime treatment of fibromyalgia patients with low-dose cyclobenzaprine was safe and appears to be effective," says Seth Lederman, MD, president of TONIX Pharmaceuticals, which funded the study.
Fibromayalgia is a condition marked by fatigue, disturbed sleep, and pain. About 5 million Americans have fibromyalgia.
Cyclobenzaprine, marketed in higher doses by others as Amrix, Fexmid, and Flexeril, is already widely used ''off-label'' for patients with fibromyalgia, Lederman says. "Off-label" refers to the practice of prescribing medicines to treat conditions not been specifically approved by the FDA.
TONIX is developing a lower-dose version and improving the formula, Lederman says.
However, a rheumatologist not connected to the study does not expect the new drug to be a ''game-changer."
The results of the study are published online in The Journal of Rheumatology.
Treatment for Fibromyalgia
Lederman and other researchers from the University of Toronto randomly assigned 18 fibromyalgia patients to take cyclobenzaprine, beginning at a dose of 1 milligram a day, and another 18 to the placebo group.
Doses were increased, as needed, up to 4 milligrams a day. Some other cyclobenzaprine products come as 5-milligram or 10-milligram tablets.
Twenty-nine patients completed the eight-week study. At the end, the researchers found that sleep quality improved. The total sleep time increased from an average of 5.7 hours to 6.4 hours in the treated group. Fatigue decreased somewhat.
Other results include:
- Pain declined 26% in the drug group over the study. That was 18% more than in the placebo group.
- Tenderness improved 30% in the drug group. That was 16% more than in the placebo group. Tenderness affects specific points on the body that are extra-sensitive to touch.
Depression declined 22% in the drug group -- 38% more than in the placebo group.
The side effects reported were similar for both groups. Headache was the most common side effect reported in the drug group. Some also had dry mouth and drowsiness.