Cymbalta, or duloxetine, is a prescription medication classified as a serotonin norepinephrine reuptake inhibitor (SNRI). Cymbalta acts on two chemicals found in the brain, serotonin and norepinephrine. Normally, these chemicals are released into the brain, where they exert their action and then get absorbed into brain cells. In individuals with depression and anxiety, the levels of the chemicals are not sufficient. Cymbalta will prevent serotonin and norepinephrine, and to some extent a third chemical called dopamine, from being absorbed back into cells in the brain, normalizing their levels. This will improve mood. Cymbalta has FDA approval for use in depression, generalized anxiety disorder (GAD), management of pain in diabetic neuropathy and management of fibromyalgia. An off-label or investigational use of Cymbalta is in the treatment of urinary incontinence.
Major Depressive Disorder
Cymbalta is useful in the treatment of depression or major depressive disorder (MDD). MDD is persistent depression that lasts for about three months or more and is displayed by loss of interest, changes in weight or sleep patterns, feelings of worthlessness and suicidal thoughts. According to Cymbalta's official site, four short-term clinical trials and one long-term clinical trial established the efficacy of the medication. The starting dose for MDD is 40 to 60 mg a day, divided into two equal doses. The maintenance dose is 60 mg per day given once a day. A dose of 120 mg a day is the maximum for MDD.
Generalized Anxiety Disorder
Generalized anxiety disorder (GAD) is defined as excessive anxiousness, nervousness and worrying occurring for six months or more. The symptoms include restlessness, difficulty sleeping, inability to concentrate and tension in muscles. Usually, these symptoms cannot be controlled. Cymbalta's efficacy in GAD was proven in three short-term clinical trials and one long-term clinical trial. The dose is 60 mg given once daily with a maximum dose of 120 mg a day.
Diabetic Neuropathy
Diabetic neuropathy is nerve damage resulting from uncontrolled diabetes. Cymbalta treats pain associated with peripheral neuropathy, or peripheral nerve damage. The peripheral nerves are the nerves that sense pain, touch and hot or cold. These nerves affect muscle and strength as well. The nerves most affected are those in the feet and lower legs. In diabetics, peripheral neuropathy can cause pain in the lower legs and feet. Cymbalta is administered once a day in a 60 mg dose in these individuals.
Fibromyalgia
Fibromyalgia is a chronic condition in which an individual feels pain in the muscles and surrounding tissues. It does not cause any harm to the muscles or tissues, but rather seems to result from the body perceiving muscle responses as pain. The dose of Cymbalta for treating the pain associated with fibromyalgia is 30 mg a day with a target dose of 60 mg a day. The maximum dose for the use in fibromyalgia is 60 mg a day.
Urinary Incontinence
According to the textbook "Pharmacotherapy: A Pathophysiologic Approach," the "results of 6 large clinical trials with duloxetine in SUI (stress urinary incontinence) have been published." Compared with placebo, duloxetine therapy produced significant reductions in incontinent episode frequency. Also, it reduced the amount of times individuals needed to urinate and increased the interval between urinations. Although the side effects of Cymbalta may cause lack of compliance, it would be the first drug approved by the FDA for treating SUI. The dosage for Cymbalta is 40 to 80 mg per day given in one or two doses.
References
- "Drug Information Handbook, 15th Edition"; Charles F. Lacy, RPh, PharmD, FCSHP, Lora L. Armstrong, RPh, PharmD, BCPS. et al; 2007
- "Pharmacotherapy: A Pathophysiologic Approach"; Joseph T. Dipiro, Robert L. Talbert, et al; 2008
- Cymbalta: Highlights of Prescribing Information
