The Facts About Chronic Fatigue Syndrome Answers to Commonly Asked Questions About Chronic Fatigue Syndrome Centers for Disease Control and Prevention National Center for Infectious Diseases Atlanta, Georgia March, 1995 Use of trade names or commercial sources is for identification only and does not imply endorsement by the Public Health Service or the U.S. Department of Health and Human Services. Background Chronic fatigue syndrome, or CFS, is a debilitating disorder characterized by profound tiredness or fatigue. Patients with CFS may become exhausted with only light physical exertion. They often must function at a level of activity substantially lower than their capacity before the onset of illness. In addition to these key defining characteristics, patients generally report various nonspecific symptoms, including weakness, muscle aches and pains, excessive sleep, malaise, fever, sore throat, tender lymph nodes, impaired memory and/or mental concentration, insomnia, and depression. CFS can persist for years. The cause of CFS has not been identified, and no specific diagnostic tests are available. Moreover, incapacitating fatigue can be associated with a wide range of well-defined illnesses, such as cancer, depression, autoimmune diseases, hormonal disorders, and subacute infections. Since many of these disorders are treatable, other causes of fatigue must be ruled out before a diagnosis of CFS can be made. Although it can be diagnosed only through this process of elimination, CFS is a genuine clinical condition whose cause and treatment are the focus of intense research. Reports about CFS have been presented at scientific meetings and published in peer-reviewed research journals. However, the body of information is still small, and many findings are preliminary. Finally, unsubstantiated anecdotal information about CFS has confused some patients and physicians regarding what is speculation and what is scientific fact. The purpose of this brochure is to provide answers to commonly asked questions about CFS and to clarify areas that are often misunderstood. _____ The Facts About Chronic Fatigue Syndrome Answers to Commonly Asked Questions About Chronic Fatigue Syndrome Clinical Aspects and Demographics Why is this illness called chronic fatigue syndrome? A number of names have been proposed over the years to describe clinical features similar to the syndrome we now call CFS. These names include chronic Epstein-Barr virus disease, chronic fatigue immune dysfunction syndrome, epidemic neuromyasthenia, and myalgic encephalomyelitis. The term chronic fatigue syndrome was agreed upon in 1988 by a group of experts studying the illness. The group unanimously selected chronic fatigue syndrome because they believed a more specific name would be misleading, given the current knowledge about the disease, and would apply only to some symptoms and patients. For example, no characteristic profile of immune dysfunction has been identified that defines chronic fatigue syndrome, and most patients do not have encephalomyelitis (inflammation of the brain and spinal cord). Chronic fatigue syndrome may not be the ideal term for the spectrum of symptoms associated with this syndrome; however, until more is understood about the underlying pathophysiological process(es) associated with CFS, changing the name would be both premature and counterproductive. If my symptoms do not fit the published case definition of CFS, does that mean I do not have CFS? The case definition published in 1988 (Holmes et al, Ann Intern Med 108:387-9) was produced by medical and public health experts at a meeting sponsored by the Centers for Disease Control (CDC). The case definition was deliberately designed to define a narrow group of patients for research purposes. More recent studies have shown that the 1988 case definition does not effectively distinguish CFS from other types of unexplained fatigue. Scientists working on CFS need to study patients who have the same carefully defined illness characteristics. For this reason, the revised case definition (Appendix A) provides additional guidelines to researchers for subgrouping cases of CFS and other types of unexplained prolonged fatigue. How many people in the United States have CFS? On the basis of results from the first several years of its ongoing physician referral-based surveillance study, CDC estimates the minimum prevalence rate of CFS in the United States at 4 to 10 cases per 100,000 adults 18 years of age or older (adjusted for age, sex, and race). Other investigators have reported substantially higher rates. CDC has recently completed the first phase of a community-based study to determine more accurately the prevalence rate of CFS. Although some media reports have indicated that more than 5 million persons in the United States have CFS, these estimates are not supported by scientific studies. Who gets CFS? In the United States, the majority of diagnosed cases of CFS occur in women, most of whom are white. Most patients are 25 to 45 years old. However, CFS has been diagnosed in a wide range of age groups, including adolescents, and in persons of different races. Diagnosis of CFS among some groups may reflect differences in culture and factors such as access to medical care. Carefully designed surveillance studies of CFS must be performed before a clear picture of its distribution in the population emerges. In its current studies, CDC has taken steps to address cultural differences and other issues that may have led to an underreporting of CFS in non-white populations. What types of cognitive dysfunction are associated with CFS? CFS patients commonly report one or more symptoms of cognitive dysfunction, including confusion, difficulty in concentrating, impaired thinking, and forgetfulness. Patients often regard these symptoms among the most debilitating features of CFS. Are there any long-term health problems associated with having CFS? No scientific evidence exists for any long-term risks associated with CFS. There are anecdotal reports of increased rates of cancer, multiple sclerosis, and other illnesses among CFS patients, but none of these claims have been scientifically established. Unlike immune deficiency diseases, such as AIDS, CFS is not associated with opportunistic infections. Unsubstantiated claims have been made that CFS patients are more prone to suicide, but there are no data to indicate that the suicide rate for CFS patients is higher than that for the general population. What is the prognosis for CFSwill I get better? Very little is known about the clinical course of CFS. It is among the most important areas of CFS research by both CDC and the National Institutes of Health (NIH). The course of this illness differs widely among patients. Some patients recover completely with time, while others seem to get progressively worse. Often, the illness follows a cyclical course, alternating between periods of illness and relatively good health. Some patients improve to a certain extent but never fully recover. Is CFS contagious? There are no published data indicating that CFS is communicable through either casual or intimate contact. Studies of groups of CFS patients and their contacts have shown no evidence of person-to-person transmission of the illness. Several cluster outbreaks of unexplained fatigue reported to CDC in recent years are being investigated. Furthermore, reports that pets are involved in the transmission of CFS, or that they can contract the disorder, are unsubstantiated. Is it safe for me to become pregnant if I have CFS? Some physicians have informally noted that the symptoms associated with CFS appear to recede during pregnancy. No controlled studies have shown evidence that CFS can be transmitted to a fetus, nor have studies shown any risks to the mother. Furthermore, no scientific evidence supports the termination of pregnancy because of any risk involving CFS. How is CFS treated? Without knowing the cause of CFS, it is difficult to identify effective treatments. Medications prescribed for CFS usually are intended to provide symptomatic relief and not a cure. However, a number of unproven and potentially dangerous treatments and diagnostic tests have been given to CFS patients at exorbitant cost. Some of the more common remedies and prescription medicines provided to CFS patients are listed in Appendix B. Are there certain medications I should avoid? In most circumstances, patients should trust in the advice of their physician. However, certain treatments, such as cyclophosphamide, azathioprine, methotrexate, and hydrogen peroxide injection, are potentially life-threatening, wholly unproven to relieve the symptoms of CFS, and should be avoided. If in doubt, call your local medical society, university medical school, or another physician. Is a particular dietary or vitamin supplement regimen recommended for people with CFS? There are no studies to suggest that dietary or vitamin supplements relieve the symptoms of or cure CFS. A list of dietary supplements and vitamins commonly used by CFS patients is included in Appendix B. Does exercise relieve symptoms or make them worse? Exercise, as well as other physically and mentally challenging activities, can exacerbate fatigue and other symptoms associated with CFS. Patients report that the effects of exercise may not be felt until 1 to 2 days after the activity. Studies are under way to determine the cause and to characterize the nature of this phenomenon. It is clear, however, that lack of exercise leads to deconditioning. Therefore, a regular regimen of moderate exercise, determined by individual tolerance, is generally recommended. Can I continue to work if I have CFS (or can my child who has CFS continue to attend school)? CFS patients may experience a variety of potentially debilitating conditions, including fatigue, arthralgia/myalgia, and difficulty concentrating, that can affect their performance on the job or in school. There is no evidence, however, that CFS can be spread from person to person. Therefore, if you feel well enough to continue working, there is no reason not to. Is it safe for me to donate blood if I have been diagnosed with CFS? Since the cause of CFS is unknown, and since it may represent a general set of symptoms caused by various factors, there is currently no formal policy or recommendation concerning donation of biological products, such as blood, by CFS patients. There are no known cases of persons who acquired CFS after blood transfusion. In general, however, persons who are not in good health, including those with CFS, are discouraged from donating blood and blood products. If you suspect you have CFS or a similar condition, inform officials at the blood collection center that you have CFS. The blood bank may have specific regulations concerning CFS or comparable illnesses. Possible Causes of CFS What causes CFS? The cause of CFS has not been identified, but there are several theories. Numerous well-characterized viruses are known to cause severe fatigue during acute infection. While some viruses, such as Epstein-Barr virus (EBV), occasionally establish a chronic active infection that results in persistent fatigue, no single virus has been firmly associated with CFS. One hypothesis is that a virus, stress, or other transient traumatic condition may chronically activate the immune system. According to this hypothesis, the immune system, which ordinarily gears down after an infection has been eliminated, remains activated after the initiating infection has passed. The result is that unusually high concentrations of immune activating factors, some of which are known to cause fatigue at high doses, persist in the bloodstream. Other theories involve proposed disturbances in the hormonal (endocrine) system, and some fatigue may be induced by psychological conditions. Another possibility is that a single causative agent, as yet unidentified, causes CFS. Is CFS caused by an uncharacterized human retrovirus? One report in the scientific literature described possible retrovirus DNA sequences in lymphocytes from CFS patients that were not present in healthy persons. Despite intensive efforts, several laboratories could not confirm the results of this study. Anecdotal reports that CFS is caused by a human spuma virus are unsubstantiated. In addition, CFS does not have any relationship to a recently reported rare disease, human immunodeficiency virus (HIV)-negative AIDS. There is also no evidence to suggest that CFS is caused by HIV-1, the virus that causes AIDS. Reduced CD4 counts are rarely observed in CFS patients. There is no evidence of life-threatening or clinically noteworthy compromise of the immune system in CFS patients. Retrovirus involvement in CFS is unlikely, although it continues to be investigated. Does human herpesvirus type 6 (HHV-6) cause CFS? HHV-6 is an extremely common herpesvirus infection that causes roseola in children and infects at least 95% of persons older than 1 year. Like all herpesviruses, HHV-6 normally remains latent within infected persons but can be reactivated periodically. Some studies have reported inconclusive evidence of HHV-6 reactivation in CFS patients; others have found no correlation between HHV-6 infection and CFS. However, since it is virtually ubiquitous in the general population, HHV-6 infection cannot be used to diagnose CFS. Do enteroviruses cause CFS? Like herpesviruses, some enteroviruses are known to cause severe fatigue and muscle weakness. Enteroviruses have been studied by several groups for their involvement in CFS. As with other potential viral causes, no strong associations can be made between recent infection by enteroviruses and CFS. Diagnosis of CFS Can CFS be diagnosed by laboratory tests? No diagnostic test exists for CFS. Currently, laboratory tests are useful solely to rule out other causes of fatigue. The same is true of serologic tests for certain viruses. Numerous scientific reports have documented immunologic differences between groups of CFS patients and healthy controls, but differences are not observed consistently, and test results between individual patients and controls overlap considerably. In other words, the test values for a randomly chosen CFS patient and those for a randomly chosen healthy person may both fall into the normal range for any of these tests. How is CFS diagnosed? CFS is currently diagnosed by a history of illness suggestive of CFS and through the systematic exclusion of other possible causes. A patient must first have profound fatigue for a minimum of 6 months. To complete the diagnosis, a physician must rule out the many clinically defined (and often treatable) causes of chronic fatigue by using a panel of routine diagnostic tests. Consult Appendix A for specific examples of illnesses that may cause severe fatigue. Are there CFS specialists who are more qualified than physicians in general practice to diagnose this illness? As with any illness, some physicians are more familiar with CFS than others, but any licensed physician should be able to diagnose CFS. Persons who suspect they might have CFS should seek a doctor with whom they have a comfortable rapport, and who has knowledge of or is open to learning about CFS. Call the nearest university-based medical center if you have difficulty locating a physician who is familiar with the syndrome. Can CFS be diagnosed by using extremely sensitive molecular tests to demonstrate the presence of retrovirus-like DNA sequences? No. One published report has been erroneously interpreted to indicate that CFS can be diagnosed by using the polymerase chain reaction method to detect human T-cell lymphotrophic virus type II (HTLV-II)-like DNA sequences in the lymphocytes of patients. However, more recent studies do not support this view. As such, this expensive research test is not useful in the diagnosis of CFS (see Possible Causes of CFS). Should diagnostic imaging techniques, such as MRI, PET scan, and SPECT scan, be used in the diagnosis of CFS? Several reports in the peer-reviewed clinical literature have described CFS patients with recognizable abnormalities seen in MRI or SPECT scans of the brain. However, these preliminary reports have not been confirmed by definitive follow-up studies and did not identify abnormalities in all CFS patients. Since the importance of these early reports is not known, these costly procedures are not appropriate for the clinical diagnosis of CFS. CFS patients have been shown to have increased antibody levels (i.e., elevated titers) to various infectious agents, including EBV, cytomegalovirus, HHV-6, rubella, enteroviruses, and Borrelia. Does this observation indicate that CFS can be triggered by the reactivation of latent infections? Some viruses, most notably the herpesviruses, can establish a state of prolonged dormancy, known as a latent infection, within their host. Such viruses normally reactivate periodically and consequently restimulate the immune system. Published studies have reported elevated titers to a number of these agents among CFS patients compared with controls. However, test values between individual patients and controls broadly overlap, indicating that such tests cannot be used to diagnose CFS. Early studies concluded that there was an association between high levels of serum antibody to EBV (which is known to cause fatigue) and CFS. However, more recent studies have shown that elevated EBV titers are not correlated with CFS. Rubella, enteroviruses, and Borrelia cannot produce a latent infection, but they can persist for prolonged periods in an infected person. Finally, because persons within a given population exhibit a broad range of titers to viruses that establish latent infections, elevated titer is difficult to define. Abnormalities of the Immune System Do CFS patients have lower-than-normal numbers of natural killer cells or natural killer cells with impaired function? Some investigators have reported lower numbers of natural killer cells or lower levels of natural killer cell activity in CFS patients than in controls. Others have been unable to observe any natural killer cell abnormalities among CFS patients. No study of natural killer cells in CFS patients has ever defined an abnormality that consistently identifies the patients. As with other experimental assays, measured levels of natural killer activity varied greatly among patients and controls, and individual test results overlapped considerably; thus, no clearly abnormal values separated all (or most) cases from all (or most) controls. Are T-cell activation markers present on a higher number of immune cells in CFS patients? One study showed that the CD8 T-cell subpopulation contained an increased number of cells expressing the activation markers CD38 and HLA-DR in a subset of CFS patients who were very ill. This finding was true for a large proportion of CFS patients (90%), but only for a small fraction of healthy controls (10%). However, similar shifts in the expression of activation markers have been observed for various acute viral infections and would be expected of any active infection. The usefulness of activation markers in diagnosing CFS remains to be established. Could elevated levels of serum cytokines indicate CFS? One of the more intriguing theories about the cause of CFS is that one of a number of possible triggering events results in a chronic activation of the immune system in these patients. If this theory is correct, one or more serum cytokine levels of CFS patients may be more elevated than those of healthy controls. Such results have been reported anecdotally for interleukin-1, for example, but no characteristic pattern of serum cytokines has been established. If I have allergies, am I more prone to get CFS? Several studies have demonstrated that some, but by no means all, CFS patients have a history of allergies. Allergy could be one predisposing factor for CFS, but it cannot be the only one, since not all CFS patients have allergies. _____ Appendix A The revised case definition of chronic fatigue syndrome (condensed from Fukuda, et al. Ann Intern Med 1994; 121:953-9.) Summary of the underlying philosophy for revising the case definition. The 1988 chronic fatigue syndrome working case definition (Holmes, et al. Ann Intern Med 1988;108:387-9) did not effectively distinguish CFS from other types of unexplained fatigue. For this reason, it was decided during a 1993 meeting of CFS investigators to develop a logical revision of that definition. The core of the revised CFS case definition is a set of uniformly applicable guidelines for the clinical and research evaluation of CFS and the other forms of fatigue. In the revised definition, a consensus viewpoint of many of the leading CFS researchers and clinicians (including input from patient group representatives), chronic fatigue syndrome is treated as a subset of chronic fatigue, a broader category defined as unexplained fatigue of 6 months or longer. Chronic fatigue, in turn, is treated as a subset of prolonged fatigue, which is defined as fatigue lasting 1 or more months. The expectation is that scientists will devise epidemiologic studies of populations with prolonged fatigue and chronic fatigue, and search within those populations for illness patterns consistent with CFS. Guidelines for the evaluation and study of CFS A thorough medical history, physical examination, mental status examination, and laboratory tests (see diagram) must be conducted to identify underlying or contributing conditions that require treatment. Diagnosis or classification cannot be made without such an evaluation. Clinically evaluated, unexplained chronic fatigue cases can be classified as CFS if the patient meets both the following criteria: 1. Clinically evaluated, unexplained persistent or relapsing chronic fatigue that is of new or definite onset (i.e., not lifelong), is not the result of ongoing exertion, is not substantially alleviated by rest, and results in substantial reduction in previous levels of occupational, educational, social, or personal activities. 2. The concurrent occurrence of four or more of the following symptoms: substantial impairment in short-term memory or concentration; sore throat; tender lymph nodes; muscle pain; multijoint pain without swelling or redness; headaches of a new type, pattern, or severity; unrefreshing sleep; and postexertional malaise lasting more than 24 hours. These symptoms must have persisted or recurred during 6 or more consecutive months of illness and must not have predated the fatigue. See the diagram and notes for additional details about the complete process for the evaluation and classification of chronic fatigue in clinical and research settings. Conditions that exclude a diagnosis of CFS 1. Any active medical condition that may explain the presence of chronic fatigue, such as untreated hypothyroidism, sleep apnea and narcolepsy, and iatrogenic conditions such as side effects of medication. 2. Some diagnosable illnesses may relapse or may not have completely resolved during treatment. If the persistence of such a condition could explain the presence of chronic fatigue, and if it cannot be clearly established that the original condition has completely resolved with treatment, then such patients should not be classified as having CFS. Examples of illnesses that can have these characteristics include some types of malignancies and chronic cases of hepatitis B or C virus infection. 3. Any past or current diagnosis of a major depressive disorder with psychotic or melancholic features; bipolar affective disorders; schizophrenia of any subtype; delusional disorders of any subtype; dementias of any subtype; anorexia nervosa; or bulemia nervosa. 4. Alcohol or other substance abuse that occurred within 2 years of the onset of chronic fatigue and any time afterwards. 5. Severe obesity as defined by a body mass index [body mass index = weight in kilograms (height in meters)2] equal to or greater than 45. Clinical Evaluation and Classification of Chronic Fatigue Any unexplained abnormality detected on examination or other testing that strongly suggests an exclusionary condition must be resolved before attempting further classification. Conditions that do not exclude a diagnosis of CFS 1. Any condition defined primarily by symptoms that cannot be confirmed by diagnostic laboratory tests, including fibromyalgia, anxiety disorders, somatoform disorders, nonpsychotic or melancholic depression, neurasthenia, and multiple chemical sensitivity disorder. 2. Any condition under specific treatment sufficient to alleviate all symptoms related to that condition and for which the adequacy of treatment has been documented. Such conditions include hypothyroidism for which the adequacy of replacement hormone has been verified by normal thyroid- stimulating hormone levels, or asthma in which the adequacy of treatment has been determined by pulmonary function and other testing. 3. Any condition, such as Lyme disease or syphillis, that was treated with definitive therapy before development of chronic symptoms. 4. Any isolated and unexplained physical examination finding, or laboratory or imaging test abnormality that is insufficient to strongly suggest the existence of an exclusionary condition. Such conditions include an elevated antinuclear antibody titer that is inadequate, without additional laboratory or clinical evudence, to strongly support a diagnosis of a discrete connective tissue disorder. A note on the use of laboratory tests in the diagnosis of CFS As indicated in the diagram, a minimum battery of laboratory screening tests should be performed. Routinely performing other screening tests for all patients has no known value. However, further tests may be indicated on an individual basis to confirm or exclude another diagnosis, such as multiple sclerosis. In these cases, additional tests should be done according to accepted clinical standards. The use of tests to diagnose CFS (as opposed to excluding other diagnostic possibilities) should be done only in the setting of protocol-based research. The fact that such tests are investigational and do not aid in diagnosis or management of the illness should be explained to the patient. In clinical practice, no tests can be recommended for the specific purpose of diagnosing CFS. Tests should be directed toward confirming or excluding other possible clinical conditions. Examples of specific tests that do not confirm or exclude the diagnosis of CFS include serologic tests for Epstein-Barr virus, enteroviruses, retroviruses, human herpesvirus 6, and Candida albicans; tests of immunologic function, including cell population and function studies; and imaging studies, including magnetic resonance imaging scans and radionuclide scans (such as single-photon emission computed tomography and positron emission tomography). _____ Appendix B Download Article Medications, herbal perparations, and miscellaneous treatments that have been used against CFS Vitamins, coenzymes, and minerals ______________________________________________________________________________ Value in treating Side effects associated with the Treatment name CFS* use of this treatment ______________________________________________________________________________ Coenzyme Q-10 F harmful effects unknown Vitamin B-12 X harmful effects unknown Vitamin C X long-term use at high dose may cause development of kidney stones Vitamin A X high doses of this vitamin can cause a wide variety of clinical symptoms, including permanent liver damage Selenium X compounds of this element may cause gastrointestinal disturbances and some are carcinogenic Germanium X harmful effects unknown Zinc X harmful effects unknown Iron X high doses of iron salts may be toxic Adenosine monophosphate F harmful effects unknown L-tryptophan F contaminated lots have been implicated in triggering eosinophilia-myalgia syndrome Magnesium sulfate X harmful effects unknown ______________________________________________________________________________ *X = no proven utility for CFS; F = no known clinical value Herbal Preparations ______________________________________________________________________________ Value in treating Side effects associated with the Treatment name CFS* use of this treatment ______________________________________________________________________________ Astragalus X harmful effects unknown Echinacea X harmful effects unknown Garlic X harmful effects unknown Ginseng X moderate use considered safe but allergic reactions have been reported. High doses may cause a variety of adverse symptoms Ginkgo biloba F harmful effects unknown Comfrey X contains tannin and lasiocarpine, both of which are considered carcinogenic. Alkaloids in comfrey may result in liver damage Primrose oil C harmful effects unknown Shiitake mushroom extract F harmful effects unknown Borage seed oil F harmful effects unknown Quercetin X harmful effects unknown Bromelain X "therapeutic doses" may cause nausea vomiting diarrhea skin rash and menorrhagia ______________________________________________________________________________ *X = no proven utility for CFS; F = no known clinical value; C = conflicting findings in clinical trials Analgesics ______________________________________________________________________________ Value in Side effects associated treating with the use of this Treatment name CFS* Examples treatment ______________________________________________________________________________ Nonsteroidal S naproxen abdominal pain/ dyspepsia/ anti-inflammatory ibuprofen nausea/ vomiting/drowsiness/ drug (NSAID) piroxicam headache/depression/ fatigue/ naproxen may impair some immune functions Other S cyclobenz- drowsiness/ dry mouth/ aprine, dizziness ______________________________________________________________________________ *S = useful for relief of symptoms Acute anxiety ______________________________________________________________________________ Value in Side effects associated treating with the use of this Treatment name CFS* Examples treatment ______________________________________________________________________________ Benzodiazepines S alprazolam sedation/ anterograde lorazepam amnesia/ withdrawal symptoms Other S buspirone dizziness/ headache/ drowsiness/ nausea ______________________________________________________________________________ *S = useful for relief of symptoms Hypnotics ______________________________________________________________________________ Value in Side effects associated treating with the use of this Treatment name CFS* Examples treatment ______________________________________________________________________________ Benzodiazepines S clonazepam hallucinations/ ataxia/ triazolam depression temazepam Other S zolpidem dizziness/headache ______________________________________________________________________________ *S = useful for relief of symptoms Antidepressants ______________________________________________________________________________ Value in Side effects associated treating with the use of this Treatment name CFS* Examples treatment ______________________________________________________________________________ Tricyclic antidepressants S doxepin dry mouth/drowsiness/ amitriptyline weight gain/ tachycardia/ desipramine weakness/fatigue nortriptyline Serotonin reuptake S fluoxetine headache/tremor/ agitation/ inhibitors sertraline nervousness paroxetine Other S trazodone drowsiness/ headache Other S venlafaxine gastrointestinal upset/ dizziness/nervousness/ elevated blood pressure Other S bupropion anxiety/agitation/ insomnia/tremor/ anorexia/ seizures ______________________________________________________________________________ *S = useful for relief of symptoms Allergy medications ______________________________________________________________________________ Value in Side effects associated treating with the use of this Treatment name CFS* Examples treatment ______________________________________________________________________________ Non-sedating antihistamines S terfenadine drowsiness/interaction with astemizole erythromycin loratidine Antihistamines S diphenhy- drowsiness dramine Other S hydroxyzine sedation ______________________________________________________________________________ *S = useful for relief of symptoms Additional drug therapies ______________________________________________________________________________ Value in Side effects associated treating with the use of this Treatment name CFS* Examples treatment ______________________________________________________________________________ Calcium channel blockers X nimodapine dizziness/ hypotension/ nicardipine headache/nausea H-2 blockers X ranitidine headache/ dizziness/nausea/ cimetidine rashes/myalgia/ impotence/ changes in immune function Immune suppressants U cyclophos- destruction of immune cells/ phamide hair loss/liver damage/ axathioprine kidney damage/ toxicity to methotrexate embryos/interstitial pneumonitis Other X naltrexone insomnia/liver damage Other X pentoxifylline gastrointestinal upset/ dizziness ______________________________________________________________________________ *X = no proven utility for CFS; U = use unjustified for CFS Miscellaneous therapies ______________________________________________________________________________ Value in treating Side effects associated with the Treatment name CFS* use of this treatment ______________________________________________________________________________ Gamma globulin C harmful effects unknown Ampligen C harmful effects unknown Kutapressin X allergic reactions Hydrogen peroxide injection F stroke High colonic enemas F intestinal disease ______________________________________________________________________________ *X = no proven utility for CFS; F = no known clinical value; C = conflicting findings in clinical trials Generic and trade names of drugs used to treat patients with CFS _____________________________________________________ Generic name Trade name _____________________________________________________ Alprazolam Xanax Amitriptyline Elavil, Endep, Etrafon, Limbitrol, Triavil Bupropion Wellbutrin Buspirone BuSpar Cimetidine Tagamet Clonazepam Klonopin Cyclobenzaprine Flexeril Desipramine Norpramin Doxepin Adapin, Sinequan Fluoxetine Prozac Lorazepam Ativan Nortriptyline Aventyl, Pamelor Paroxetine Paxil Pentoxifylline Trental Ranitidine Zantac Sertraline Zoloft Temazepam Restoril Trazodone Desyrel Triazolam Halcion Venlafaxine Effexor Zolpidem Ambien _____________________________________________________ CDC maintains a 24-hour voice information system that provides up-to-date information on chronic fatigue syndrome. The number for the information system is (404) 332-4555.