As medical science understands more about fibromyalgia syndrome (FMS), pharmaceutical companies are racing to get the FDA to approve existing drugs as fibromyalgia treatments. Doctors prescribe a broad range of medications off-label because they've found them to be effective. Studies into some drugs are yielding promising results.
Drugs Approved as Fibromyalgia Treatments
Lyrica (pregabalin): In June 2007, Lyrica became the first medication to be FDA approved as a fibromyalgia treatment. In clinical trials, people with FMS showed significant improvement in pain, sleep, fatigue and quality of life. Manufactured by Pfizer, Lyrica also is approved for treating the pain of diabetic neuropathy and postherpetic neuralgia. It's also used, in combination with other drugs, to prevent partial-onset seizures in epileptic adults.
It may sound odd, but Pfizer isn't exactly sure why Lyrica works. This is what it says on the FDA's website:
The mechanism of action is unknown, but there is some data suggesting that it has effects on the release of neurotransmitters in the brain. Neurotransmitters are chemicals in the brain that transmit signals from one neuron to another.
Cymbalta (duloxetine): The FDA approved Cymbalta as a fibromyalgia treatment in June 2008. Cymbalta is classified as an SNRI, or serotonin-norepinephrine reuptake inhibitor. Serotonin and norepinephrine are both neurotransmitters that are generally deficient in people with fibromyalgia. SNRIs make more of them available to the brain.
Cymbalta was previously FDA-approved for treating depression and diabetic neuropathy.
Seeking Approval as Fibromyalgia Treatments
Milnacipran: A drug new to the U.S., milnacipran is now navigating the FDA process for being approved to treat FMS. Made by Forest Laboratories and Cypress Bioscience, milnacipran is an antidepressant similar to Cymbalta, except that milnacipran is the first drug to increase norepinephrine more than serotonin.
The New Drug Application includes data from two Phase III trials involving more than 2,000 patients. The company says data show milnacipran was more effective than a placebo and was well-tolerated, with the majority of side effects described as mild to moderate.
Milnacipran is sold in Europe under the names Dalcipran and Ixel, has been on the market for a decade and is approved for depression in more than 50 countries.
JZP-6 (sodium oxybate): Clinical trials of JZP-6 (the active ingredient in Xyrem) showed that it significantly improved sleep quality and reduced pain in fibromyalgia patients. JZP-6 is a central nervous system depressant and is thought to help the patient attain the deeper stage 3 and stage 4 levels of sleep. Phase III clinical trials wrapped up in Sept. 2008 and at that time Jazz Pharmaceuticals anticipated sending a New Drug Application to the FDA by the end of 2009.
Marketed by Orphan Medical, Xyrem is FDA-approved for cataplexy (sudden loss of muscle control) in patients with narcolepsy. Note: Because of its potential for abuse, Xyrem is a Schedule III federally controlled substance.
Other Drugs Used as Fibromyalgia Treatments
Antidepressants: Antidepresants raise levels of certain chemicals in the brain, including the neurotransmitter serotonin and the stress hormone norepinephrine -- both are low in people with depression or FMS.
- Dual Reuptake Inhibitors: This class includes Cymbalta and milnacipran. Other examples of these drugs are: venlafaxine and nefazodone.
- Tricyclic Antidepressants: If taken at night, these drugs can help people with fibromyalgia get better-quality sleep. They also increase the effects of pain-killing endorphins and help relax sore muscles. Some tricyclic antidepressants commonly used to treat fibromyalgia include: amitriptyline, doxepin and nortriptyline.
- Selective Serotonin Reuptake Inhibitors (SSRIs): These drugs get the brain to release more serotonin, which helps regulate sleep, and they sometimes help people with fibromyalgia feel less tired and get relief from other symptoms. However, they can interfere with sleep. Examples of SSRIs are: fluoxetine, paroxetine and sertraline.
All of the medications listed here have potential side effects and can cause serious medical issues if you stop taking them too suddenly. It's important to stay in touch with your doctor to discuss any problems or dosage changes.
- To see lists of side effects and check drug interactions, visit the About.com Drug Finder.
- If you adverse reactions to a medication, be sure to report it through the FDA Safety Information and Adverse Event Reporting Program.
Sources:
NIH Publication NO. 04-5326
June 2007, U.S. Food and Drug Administration, "Living with Fibromyalgia"
