Fibromyalgia - Medications

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Generally, only small doses of tricyclic antidepressants are needed to relieve fibromyalgia. Therefore, although tricyclics have several side effects, these side effects may be less frequent in fibromyalgia patients than in those taking tricyclics for depression. Side effects most often reported include:

• Blurred vision
• Difficulty urinating
• Dizziness
• Drowsiness
• Dry mouth
• Heart rhythm disturbances
• Sexual dysfunction
• Weight gain

As with all medications, tricyclic antidepressants must be taken as directed. An overdose can be life threatening.

Unfortunately, not all patients respond to tricyclics, and the effects wear off in some patients, sometimes after only a month.

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Selective Serotonin-Reuptake Inhibitors. Selective serotonin-reuptake inhibitors (SSRIs) increase serotonin levels in the brain, which may have specific benefits for fibromyalgia patients. Commonly prescribed SSRIs include fluoxetine (Prozac), sertraline (Zoloft), paroxetine (Paxil), and fluvoxamine (Luvox). Studies suggest they may improve sleep, fatigue, and well-being in many patients. Studies are mixed on whether they improve pain. SSRIs should be taken in the morning, since they may cause insomnia. Common side effects are agitation, nausea, and sexual dysfunction, including a delay or loss of orgasm and low sex drive.

Serotonin-Norepinephrine Reuptake Inhibitors. Serotonin-norepinephrine reuptake inhibitors (SNRIs) are also known as dual inhibitors because they act directly on two chemical messengers in the brain -- norepinephrine and serotonin. These drugs appear to have more consistent benefits for fibromyalgia pain than SSRIs. They also tend to have fewer side effects than the tricyclics and are generally tolerated well.

SNRIs include:

• Duloxetine (Cymbalta) has been approved by the FDA for treating fibromyalgia. In studies, it reduced fibromyalgia pain by more than 30%. The most common side effects with this medication are nausea, dry mouth, constipation, decreased appetite, sleepiness, increased sweating, and agitation. It may also increase the risk of hemorrhage in patients taking NSAIDs, aspirin, or blood thinners.
• Milnacipran (Savella) can significantly improve pain and physical function in fibromyalgia patients. Milnacipran is not approved for use in children. The label includes a boxed warning that it may increase the risk of suicidal thoughts and behaviors in children and adolescents. Savella is also not appropriate for patients who are taking monoamine oxidase inhibitors, and for those with uncontrolled narrow-angle glaucoma.
• Venlafaxine (Effexor) is similar to fluoxetine (Prozac) in effectiveness and tolerability for most patients. As with SSRIs, and unlike other newer antidepressants, venlafaxine impairs sexual function. Although clinical trials have shown that the drug is safe and effective in most people, there have been reports of changes in blood pressure. There have also been reports of problems with the electrical system of the heart in people taking this drug. These side effects may cause serious problems in elderly patients. Some patients report severe withdrawal symptoms, including dizziness and nausea.