The drug sodium oxybate relieves pain and improves function, with few side events, in people who suffer from the chronic pain syndrome known as fibromyalgia, researchers report in the January issue of Arthritis and Rheumatism.
Sodium oxybate is approved in the US for the treatment of excessive daytime sleepiness in patients with narcolepsy, a condition that causes people to fall asleep involuntarily, and for the treatment of cataplexy, a sudden weakness in the muscles that accompanies narcolepsy.
Dr. I. Jon Russell of University of Texas Health Science Center at San Antonio and colleagues studied the effects of sodium oxybate in 188 fibromyalgia patients. After discontinuing their pre-study medications, the patients were randomized to sodium oxybate or matching placebo once nightly for 8 weeks.
One hundred forty-seven patients (78 percent) completed the trial and, according to the researchers, patients taking sodium oxybate reported significantly less pain and improved sleep and quality of life, relative to patients taking placebo.
"Sodium oxybate therapy was well tolerated and significantly improved the primary outcome variables," Dr. Russell told Reuters Health. "In addition, significant improvement was seen with many of the secondary outcome variables which addressed a wide variety of the fibromyalgia syndrome symptoms."
Less than 28 percent of patients reported nausea and less than 18 percent reported dizziness. Most episodes tended to resolve and caused few patients to withdraw from the study.
The investigators conclude that "this proof-of-concept study suggests that sodium oxybate is effective and safe for the management of fibromyalgia syndrome symptoms," and that further investigation is warranted.
SOURCE: Arthritis and Rheumatism, January 2009.