Fibromyalgia – New Treatments
Fibromyalgia (FM or FMS) is a condition that causes chronic musculoskeletal pain. In addition to generalized pain, it is characterized by tender points – painful areas located on certain parts of the body. Often there are other symptoms as well, such as fatigue, headaches, cognitive problems, sleep disturbances, anxiety, and depression.
People with fibromyalgia frequently have other comorbid conditions, such as chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME), migraines, restless legs syndrome (RLS), and irritable bowel syndrome (IBS). Fibromyalgia commonly occurs along with autoimmune diseases, especially rheumatoid arthritis and lupus (SLE), but it is not thought to be an autoimmune disease. The exact mechanism that causes the disease is not yet fully understood.
lyrica and cymbalta
The FDA approved two medications for fibromyalgia: pregabalin (Lyrica) in June 2007 and duloxetine (Cymbalta) in June 2008. Pregabalin is an anticonvulsant (epilepsy medication), although it is most often used for pain disorders. . Duloxetine is a SNRI (serotonin and norepinephrine reuptake inhibitor) antidepressant, also used for diabetic neuropathy and stress incontinence.
Despite being in completely different classes of drugs, both Lyrica and Cymbalta can relieve pain, sleep problems, fatigue, cognitive decline, depression, and anxiety caused by fibromyalgia, although they don’t help everyone and even if benefits, you may not get improvement in all of the symptoms listed.
other similar drugs
Of course, the pharmaceutical companies behind these drugs would like us to believe that they are the magic bullets, but luckily there are many other drugs that can help with fibromyalgia. The makers of most other drugs simply haven’t invested in the expensive trials necessary to gain FDA approval, often because the patent will soon expire and then their benefits will decline dramatically.
For example, gabapentin (Neurontin) is an anticonvulsant very similar to Lyrica, which used to be widely prescribed for fibromyalgia, but now Lyrica has superseded it. The drugs have nearly identical modes of action. There is no clear evidence to show that either is more effective. Some people can tolerate pregabalin but not gabapentin and vice versa. Neurontin comes with a slightly cheaper price.
Duloxetine is not the only SNRI antidepressant either. Venlafaxine (Effexor) is also an SNRI, although in low doses it does not have as much of an effect on norepinephrine. Milnacipran (Ixel) is a promising SNRI antidepressant that is not yet available in the United States, but is sold in most of Europe. It has shown good results in preliminary fibromyalgia trials. It is also very inexpensive and is believed to be one of the best tolerated antidepressants.
Anticonvulsants And Antidepressants
In general, almost all anticonvulsants, including older names like carbamazepine and lamotrigine and newer ones like topiramate, zonisamide, and levetiracetam, can relieve fibromyalgia symptoms. There are vast differences in modes of action between drugs in this class, so even if one doesn’t work or produces intolerable side effects, another is worth trying. They tend to be especially helpful for pain, mood issues, and migraine prevention, often for sleep as well.
The same goes for antidepressants, too. The reason they are used in fibromyalgia is not that fibromyalgia is a psychiatric disorder, but that they are also used in many other painful conditions such as migraines, chronic headaches, neuropathic pain, and IBS. It is believed that fibromyalgia may be associated with a deficit of serotonin and norepinephrine.
SSRI antidepressants such as fluoxetine (Prozac) are generally not as effective for pain. However, many other antidepressants also affect norepinephrine. These include tricyclic antidepressants such as amitriptyline (Elavil) and imipramine that have been used to treat fibromyalgia since the 1980s. They are used in very small doses, usually much smaller than would be used for depression. They are especially effective for sleep, but they often cause too many side effects.
NMDA antagonists
A third promising class of drugs are the NMDA receptor antagonists. The NMDA receptor is thought to be overactive in fibromyalgia, and its downregulation could alleviate all symptoms of the condition. NMDA antagonists include the cough suppressant dextromethorphan, amantadine, which is used for influenza and Parkinson’s disease, the Alzheimer’s drug memantine, and riluzole, a new drug used for amyotrophic lateral sclerosis (ALS). ).
Other drugs that also downregulate the NMDA receptor include, for example, calcium channel blockers, many anticonvulsants, some opioids (methadone and dextropropoxyphene), and the muscle relaxants dantrolene and orphenadrine. Magnesium and the amino acid taurine may also have this effect.
Hormone Treatments
Fibromyalgia has also been associated with endocrine (hormonal) deficiencies, especially of growth hormone, thyroid hormone, and vitamin D, which is now considered a steroid hormone. Others, such as estrogen, testosterone, and cortisol, have also been suggested as culprits.
Growth hormone has been shown to be deficient in a subset of people with fibromyalgia and supplementation helps many people. Unfortunately, the treatment must be given by injection and is very expensive. Fortunately, some oral medications can also increase growth hormone secretion, such as buspirone, an anti-anxiety medication, clonidine, a blood pressure medication, and baclofen, a muscle relaxant. Melatonin can also have this effect.
Some doctors believe that thyroid supplementation may even completely relieve fibromyalgia symptoms in some cases where laboratory results are presumed normal. On the other hand, many patients have reported excellent results, including complete pain relief with large doses of vitamin D.
Promising drug candidates
Many drugs are currently in clinical trials for fibromyalgia. Sodium oxybate (Xyrem) is a sleep aid that can also help with depression and pain. It is currently approved for narcolepsy, but is used off-label for severe insomnia. Several trials have shown good efficacy in fibromyalgia, but insurance companies are likely to frown on the price.
Flupirtine (Katadolon) is used in many European countries, for example, for low back pain. It has some NMDA blocking properties and has shown good efficacy in preliminary trials. If clinical trials are successful, the company plans to market it for fibromyalgia under the brand name Effirma.
Lacosamide (Vimpat) is an anticonvulsant with a new mode of action. It is not yet on the market, but it may be approved in the United States and Europe before the end of 2008. A recent phase IIa trial concluded that it was effective and well tolerated in fibromyalgia.
Low-dose naltrexone (LDN) is a treatment that increases the secretion of endorphins, our natural pain relievers. Fibromyalgia can be associated with an endorphin deficiency, which could also contribute to fatigue, depression, and other symptoms. A clinical trial testing LDN for fibromyalgia is currently running in the United States.
