As is often the case with medications, taking drugs for fibromyalgia can involve some risk. Dizziness, drowsiness and an upset stomach are often side effects of fibromyalgia medication. Swelling and weight gain are also common. People with fibromyalgia often are already struggling with a tendency to put on unwanted pounds so this side effect can be quite a problem.
A dry mouth and high blood pressure are possible side effects as well. Suicidal thoughts, depression and problems with concentration can make the cognitive difficulties frequently associated with fibromyalgia even more difficult to deal with.
If you are taking other drugs as well, you can experience unpleasant interactions between these medications. Taking multiple medications can make serotonin levels go too high. Anxiety and a racing heart can be the result.
"There are three fibro drugs on the market: Cymbalta, Lyrica, and Savella. (Other drugs may be used off-label, meaning they aren't specifically approved to treat fibro.)"
http://health.msn.com/medications/articlepage.aspx?cp-documentid=100261392