POTENTIAL BENEFITS OF ANTIDEPRESSANT THERAPY
Fibromyalgia is a chronic condition for which no cure currently exists. The first approach to treatment is the use of palliative nonpharmacological therapy. Various approaches include massage therapy, hypnotherapy, behavioral therapy, acupuncture, and aerobic exercises (e.g., swimming) that do not place added stress on affected areas. These therapeutic modalities offer only limited benefit and should be combined with pharmacological agents that are aimed at reducing the pain and other bothersome symptoms.
Diet may also play a role in stimulating or worsening patients’ symptoms. Many health care professionals agree that certain fatty, fried, or sugary foods might act as possible triggers of pain. It is recommended that patients eat whole foods such as vegetables, whole grains, fruits, and protein. Caffeine should be avoided, because even small amounts can lead to sleep disturbances.
Possible therapeutic agents that have been used to relieve the symptoms of fibromyalgia include:
Because fibromyalgia is not necessarily associated with important inflammatory processes, the following NSAIDs provide minimal to modest benefit:
Benzodiazepines such as diazepam (Valium®, Roche) have been used to aid sleep and muscle relaxation and to alleviate restless legs syndrome. However, these agents are not used very often because of their possible potential to be addictive.
Tramadol, a central-acting analgesic, has the additional action of inhibiting norepinephrine and serotonin reuptake; therefore, it may be used as a possible alternative treatment.
Cyclobenzaprine is structurally related to the tricyclic anti-depressants (TCAs) and has effects similar to those of ami-triptyline (see later).
Certain antidepressants, (Forest), sertraline (Zoloft®, Pfizer), and (Wyeth-Ayerst), have been evaluated in the treatment of fibromyalgia, and preliminary studies involving selective serotonin reuptake inhibitors (SSRIs) are beginning to emerge in the literature.
One agent that has been evaluated in clinical studies is the TCA (e.g., AstraZeneca; Endep®, Roche). Amitriptyline acts by inhibiting serotonin and nor-epinephrine reuptake and therefore increases serum concentrations of these two neurotransmitters. Through randomized placebo-controlled studies, amitriptyline has been shown to be effective at lower doses than in the treatment of depression (i.e., 10 mg at bedtime). The sedative effects of amitriptyline have proved beneficial to patients because it allows a more peaceful sleep.
One major disadvantage of amitriptyline is the incidence of extensive anticholinergic side effects (dry mouth, blurred vision, constipation, and urinary retention). Clinical data have confirmed that amitriptyline provides short-term improvement outcomes, but long-term efficacy has not been established because of the placebo effect. Other TCAs have not been extensively studied.
SSRIs have also been considered as a potential therapeutic regimen in the treatment of fibromyalgia. As a result of their high selectivity for blocking serotonin receptors, some specialists hypothesize that there might be a potential bene-fit. SSRIs are also better tolerated than TCAs.
Fluoxetine medication (Prozac canadian, Eli Lilly) has been evaluated in double-blind clinical trials to determine its efficacy. The drug has proved to exhibit pain-reduction capabilities according to various pain measures and questionnaires, and further study is warranted. One study showed more improvement when fluoxetine was combined with a TCA. Patients who took citalopram and sertraline have also shown improvement. However, these studies were limited in various ways, and the results have not been properly validated.
General weaknesses that characterize the studies involving SSRIs include a sample size that was too small, short follow-up with drug therapy, and high dropout rates. Because of their favorable safety profiles, it is possible that these agents will prompt future studies. In addition, because depression can be associated with fibromyalgia, the two conditions might be treated with one therapeutic agent.
Fibromyalgia is a continuous burden on the lifestyle of affected individuals. It is commonly associated with pain at various tender points. On the basis of the current wisdom regarding the pathophysiology of the disorder, drug therapy is currently targeted at correcting various neurotransmitter abnormalities. Serotonin has been singled out in particular because of its implications regarding the pathophysiology of fibromyalgia in the production of pain. Antidepressants have been evaluated in clinical trials to determine their effectiveness in the treatment of fibromylagia. Amitriptyline has proved beneficial, but its long-term efficacy has not been established. SSRIs also show promising beneficial effects, but further studies are required to validate the results. Longer-term and more extensive studies of at least 500 or more patients should be conducted for at least one year to confirm the results of these preliminary studies.