Only a minority of patients with moderate to severe fibromyalgia get pain relief from the antiepileptic pregabalin, but the quality of that pain relief is strong, an updated review of the related literature concludes.
"Pregabalin works extraordinarily well in 1 person in 10 who has fibromyalgia and it doesn't work for the other 9 patients, and that's probably the same for almost any drug that you might want to use in fibromyalgia," said study author R. Andrew Moore, PhD, DSc, a senior pain researcher at the University of Oxford, United Kingdom.
"The good news is that when it works, it works not just on the pain, but for sleep, for depression, for quality of life, and for the ability to work. People's lives can be transformed by getting rid of the pain."
Like some other drugs, pregabalin is "worth a try," and if it doesn't work within about 6 weeks, "it's never going to work," said Dr Moore.
The new review was published online September 29 in theCochrane Database of Systematic Reviews.
The review is an update of one originally published in 2009 that examined the effects of pregabalin in all types of pain. This more recent review included only studies of patients with fibromyalgia.
Fibromyalgia is characterized by persistent, widespread pain and tenderness, sleep problems, and fatigue. The condition is "not uncommon" and "affects mostly women in their 50s when they're perhaps most productive, whether it's in the home or the workplace, and it can be quite devastating," said Dr Moore.
Common pain-relieving medications, such as acetaminophen (paracetamol) and ibuprofen, are not usually effective, but drugs used to treat epilepsy or depression can be helpful in relieving pain.
Pregabalin (Lyrica, Pfizer, as well as other generic brands) is an antiepileptic agent also licensed to treat fibromyalgia in the United States and some other parts of the world, although not the United Kingdom.
New Studies
Researchers searched scientific databases for studies of the effects of pregabalin in adults with fibromyalgia who had moderate to severe pain.
The review included eight studies, among them three new published papers. Two of these new studies were of classic design in which patients were randomly assigned at the start of the study to pregabalin or placebo. One used a more sensitive design called enriched enrollment randomized withdrawal, in which participants who had a good pain response and could tolerate the medicine were first identified and then randomly assigned to continued treatment with pregabalin or placebo.
The studies were all randomized and double-blind and included mainly women in their 50s, but they often excluded people with depression. They lasted a minimum of 8 weeks, but one lasted 6 months.
The primary outcome used was changes to the Global Impressions of Change scale. The initial average pain score of study participants was 7 of 10. Their average duration of symptoms was 4 years.
Studies had a low risk of bias, except that the last observation carried forward imputation method used in analyses of the primary outcomes could overestimate treatment effect, according to the authors.
source : http://www.medscape.com/viewarticle/870199
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