By Dr Ananya Mandal, MD
Fibromyalgia is a chronic pain condition that is typically manifested as widespread pain, impairment of daily living functions, sleep disturbance and lack of sleep, presence of typical tender points over the body etc. There are other symptoms such as non-restorative sleep and fatigue.
There are several studies that show that a drug approved for use in a condition called Narcolepsy may help patients with sleep and fatigue problems in fibromyalgia.
The drug in question is called sodium oxybate. Studies have shown sodium oxybate to reduce non-restorative sleep abnormalities.
To date, only one drug, pregabalin, has been approved for the treatment of fibromyalgia. There is a need to expand the pharmacologic options.
What is sodium oxybate?
Sodium oxybate is a metabolite of gamma aminobutyric acid and is approved by the US Food and Drug Administration (FDA) for the treatment of cataplexy and excessive daytime sleepiness in patients with narcolepsy.
In narcolepsy this drug consolidates fragmented sleep, increases duration of deep or slow-wave sleep and reduces night-time awakenings.
In one of the late stage clinical trials with sodium oxybate in fibromyalgia 573 patients with fibromyalgia who fulfilled the American College of Rheumatology criteria were enrolled. They were randomly assigned to three groups with one receiving 4.5 g Sodium Oxybate, one receiving 6g Sodium Oxybate and one group receiving placebo or dummy pills.
After the study patients were assessed for pain reduction, tenderness at the trigger or tender points, sleep quality, fatigue, health-related quality of life and subject’s own assessment of improvement and wellbeing.
Results from the study showed that pain, sleep and other symptoms associated with fibromyalgia improve significantly with sodium oxybate. Around 42% reported over 30% pain reduction with 4.5g sodium oxybate while 51.4% reported over 30% pain reduction with 6g sodium oxybate.
Sleep improved by 20% with 4.5 g sodium oxybate and 25% for 6g sodium oxybate as measured by Jenkins sleep scale.
Both pain relief and sleep improvement with the drugs were significantly greater than with dummy pills or placebo. Patients on sodium oxybate, however, suffered from some common side effects including nausea, dizziness, vomiting, muscle spasms and leg swelling or edema.
Reviewed by April Cashin-Garbutt, BA Hons (Cantab)
Last Updated: Aug 18, 2013