Cymbalta (duloxetine) is classified as an SNRI, or serotonin norepinephrine reuptake inhibitor. It was FDA approved as a fibromyalgia treatment in June 2008, and it's also approved as a treatment for depression and diabetic neuropathy.
Serotonin and norepinephrine are neurotransmitters (chemical messengers in the brain); their metabolism is believed to be abnormal in people with fibromyalgia. This hypothesis has been growing in strength, especially since Cymbalta and other drugs in its class -- which work by making more of these chemicals available to the brain -- have been successful in clinical trials.
Multiple clinical trials show that Cymbalta can reduce fibromyalgia pain, both with and without comorbid depression. Studies also show that the drug continues to be effective for at least one year.
The recommended Cymbalta dosage is 60 mg, taken once a day. It's generally started at 30 mg a day and then increased to 60 mg after about a week. Doses higher than this aren't believed to be more effective, and they are associated with a higher risk of side effects. People who want to stop taking Cymbalta should talk to their doctor to learn how to lessen withdrawal symptoms.
Cymbalta is associated with numerous possible side effects. Those that you should report to your doctor right away include:
- Allergic reactions (rash, itching or hives, swelling of the face, lips or tongue)
- Blood pressure changes
- Confusion
- Dizziness and/or loss of balance
- Fast talking, excited feelings, or out-of-control actions
- Rapid, irregular heartbeat
- Fever
- Hallucinations or loss of contact with reality
- Seizures
- Diarrhea, vomiting
- Suicidal thoughts or other mood changes
- Dark urine
- Unusual bleeding or bruising
Side effects that don't usually require medical attention include:
- Blurred vision
- Appetite changes
- Changes in sex drive or performance
- Headache
- Increased sweating
- Nausea
Sources:
About.com Drugs A-Z. All rights reserved. "Cymbalta"
NIH Publications NO. 04-5326
The Clinical Journal of Pain. 2009 Jul-Aug;25(6):461-8. "Comparisons of the efficacy and safety of duloxetine for the treatment of fibromyalgia in patients with versus without major depressive disorder."
Clinical Rheumatology. 2009 Jun 18. [Epub ahead of print] "Safety and tolerability of duloxetine in the treatment of patients with fibromyalgia: pooled analysis of data from five clinical trials."
