Fibromyalgia and Chronic Opioid Analgesic Therapy
Fibromyalgia symptoms are familiar to those who live with it every day. The throbbing muscle aches, shooting pains, soft tissue tenderness, the twitching spasms, fatigue, and restless sleep. There is no "best treatment" for this syndrome, however. A myriad of remedies have been tried, but what works for one person, doesn’t necessarily work for another.
Some patients respond to alternative therapies, such as hypnosis or cupping (a Chinese medicine therapy) while others may require narcotic medications or spinal nerve blocks. But what works today, may not necessarily help tomorrow, as symptoms of FM wax and wane.
Fibromyalgia patients can be placed on chronic opioid analgesic therapy, or COAT, when other attempts at pain control have failed. Opioids, also known as narcotics, are pharmaceutical drugs derived from the poppy plant. These medications include morphine derivatives and synthetic drugs made to mimic the effects of morphine. Opioids work by blocking opioid receptors in the brain—the areas of the nerve that process pain signals from the body.
This particular class of drugs effectively treats fibromyalgia syndrome, but has been under scrutiny due to a lack of data about its effectiveness to treat nonmalignant, chronic pain. Few clinical trials exist that address the use of opioids to treat persistent pain in FM patients.
To clarify points surrounding the debate over the use of opioids to treat FM, posters of study data were presented at the American Pain Society meeting held May 3 - 6, 2006 in San Antonio, Texas.
A study of 81 FM patients within a population of 1428 patients with chronic, nonmalignant moderate-to-severe pain was conducted to compare pain and function in patients who used Kadian® (extended-release morphine sulfate capsules). The patients in this study had inadequately treated pain based on evaluation of previously used medications.
The researchers found statistically significant improvements in quality-of-life test scores that measured physical function, physical component, body pain, general health, vitality, social functioning, emotional component, and mental health. Patients and clinicians also completed additional assessments of pain, sleep, and therapy. Kadian was administered once daily in a dose tailored to the patient based on previous pain medication use, with adjustments after one or two weeks, with twice-daily dosing after two weeks as needed. The few patient complications noted were those usually associated with morphine-based medications, including constipation and nausea.
The effectiveness of Kadian is because of the drug’s delivery mechanism. The morphine is contained in microspheres that break down in a uniform fashion.
Other drugs in the class that claim to be sustained release should actually be classified as intermediate. "They do not pan out on evaluation," said Bruce D. Nicholson, MD, the director of the Division of Pain Management/Center for Pain Management at Lehigh Valley Hospital and Health Network. "There isn’t another preparation like Kadian out there."
More women than men were affected by fibromyalgia in this study (approximately 90 percent of the pain group). Although women tend to visit physicians more consistently with pain complaints in general, FM does seem to have a physiological component specific to females. "There is no question that females have a higher percentage of fibromyalgia," Nicholson.
The study was conducted by Dr. Nicholson; Edgar L. Ross, MD, Director, Pain Management Center, Brigham & Women’s Hospital, Boston, MA and assistant professor of anesthesia at Harvard Medical School; John Sasaki, MD, Director, Pain Management, Casa Colina Hospital and HealthSouth Upland, Pomona, CA; and Arnold J. Weil, MD, CEO and founder of Non-Surgical Orthopaedic and Pain Center, P.C. and clinical assistant professor of rehabilitation medicine at Emory University School of Medicine, Atlanta, GA.
The use of opioids to treat pain is justified by the Federation of State Medical Boards Model Guidelines for the Use of Controlled Substances for the Treatment of Pain, according to Scott M. Fishman, MD, Chief of the Division of Pain Medicine at the University of California at Davis School of Medicine, Sacramento. "Opioid analgesics are still our gold standard," said Fishman at the 2005 meeting of the American Society of Regional Anesthesia and Pain Medicine.
Opioids are meant to improve function in the FM patient who is impaired by pain. These drugs are particularly useful in treating flares of pain that can occur in FM.
Nonetheless, certain factors contribute to the debate over the use of opioids to treat FM pain, including issues related to drug abuse, addiction, and increased pain sensitivity. Consequently, some physicians may believe narcotics are too strong or not appropriate for the type of pain associated with FM. However, this class of drugs is useful in patients who do not respond to other medications. Steven D. Feinberg, MD, of the Bay Area Pain and Wellness Center in Los Gatos, Calif., was quoted in CWCE Magazine as saying: "Some physicians would consider using opioids for myofascial pain or fibromyalgia akin to using a sledgehammer to put in a thumbtack."
Physicians need to be ever vigilant to the potential for drug-seeking behavior by addicts or those seeking to acquire the drug for recreational purposes. Some of the drug abuse potential of opioids like Kadian is diminished, though, since the extended release version prevents some of the initial boost of the drug upon administration in its prepared form.
However, physicians need to be aware that the pain associated with FM is very real, and can be further exaggerated by drug tolerance. Addiction to opioid analgesics is reported in 3 to 19 percent of patients with chronic pain, said Fishman. An obvious health concern related to narcotic addiction is the physical component of withdrawal.
In addition to opioids such as Kadian, several other categories of drugs have been used in the attempt to treat fibromyalgia. These medications include various antidepressants (such as benzodiazepines, tricyclic antidepressants, selective serotonin reuptake inhibitors, and serotonin norepinephrine reuptake inhibitors), beta adrenergic receptor blockers, Cox-II inhibitors, dopamine receptor agonists, dextromethorphan, gamma-hydroxybutyrate (GHB), human growth hormone, sedatives, muscle relaxants, and various topical and patch preparations. Some of these medications only have been tried in clinical trials, particularly those that have potential for abuse (such as GHB).
