Cymbalta

Cymbalta is the brand name for duloxetine, a prescription serotonin-norepinephrine reuptake inhibitor (SNRI) used to treat certain mood disorders and chronic pain conditions. In the United States, duloxetine is approved for major depressive disorder, generalized anxiety disorder, diabetic peripheral neuropathy, fibromyalgia, and chronic musculoskeletal pain (such as osteoarthritis or low back pain). The drug is available as oral capsules.

Mechanism and pharmacology: Duloxetine increases the levels of the neurotransmitters serotonin and norepinephrine in the central nervous system by inhibiting their reuptake into presynaptic neurons. It also has weak dopaminergic effects at higher doses. Duloxetine is metabolized mainly in the liver by the enzymes CYP1A2 and CYP2D6, and it is a moderate inhibitor of CYP2D6, which can affect the metabolism of other drugs. The elimination half-life is typically around 12 hours, and a steady state is reached within several days. About half to two-thirds of a dose is excreted in the urine.

Dosing and administration: Starting and target doses vary by condition. Commonly, for major depressive disorder and generalized anxiety disorder, starting at 40 mg once daily with gradual increases up to a usual maximum of 120 mg daily. For diabetic neuropathy, fibromyalgia, and chronic musculoskeletal pain, starting doses of 30–60 mg daily may be used, with gradual titration up to 60–120 mg daily. Duloxetine can be given once daily; if dosing above 60 mg, some regimens use once-daily dosing. Dose adjustments are slower in older adults or those with liver impairment.

Safety and interactions: Duloxetine may cause nausea, dry mouth, fatigue, insomnia or sleep disturbance, dizziness, reduced appetite, and sexual dysfunction. It can raise blood pressure and interact with other serotonergic drugs, increasing the risk of serotonin syndrome. Discontinuation should be gradual to limit withdrawal symptoms. Contraindications include concurrent monoamine oxidase inhibitors and hypersensitivity. Caution is advised in liver disease, substantial alcohol use, glaucoma, and elderly patients. Pregnancy category C; duloxetine passes into breast milk.

Brand and generic status: Cymbalta is the brand name; duloxetine is available as a generic medication.