Duloxetine is used to treat depression in adults and generalized anxiety disorder (GAD; excessive worry and tension that disrupts daily life and lasts for 6 months or longer) in adults and children 7 years of age and older. Duloxetine is also used to treat pain and tingling caused by diabetic neuropathy (damage to nerves that can develop in people who have diabetes) in adults and fibromyalgia (a long-lasting condition that may cause pain, muscle stiffness and tenderness, tiredness, and difficulty falling asleep or staying asleep) in adults and children 13 years of age and older. It is also used to treat ongoing bone or muscle pain such as lower back pain or osteoarthritis (joint pain or stiffness that may worsen over time) in adults. Duloxetine is in a class of medications called selective serotonin and norepinephrine reuptake inhibitors (SNRIs). It works by increasing the amounts of serotonin and norepinephrine, natural substances in the brain that help maintain mental balance and stop the movement of pain signals in the brain.
Duloxetine comes as a delayed-release (releases the medication in the intestine to prevent break-down of the medication by stomach acids) capsule to take by mouth. When duloxetine is used to treat depression, it is usually taken once or twice a day with or without food. When duloxetine is used to treat generalized anxiety disorder, the pain of diabetic neuropathy, fibromyalgia, or ongoing bone or muscle pain, it is usually taken once a day with or without food. Take duloxetine at around the same time(s) every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take duloxetine exactly as directed. Do not take more or less of it, take it more often, or take it for a longer time than prescribed by your doctor.
Summary from MedlinePlus.gov, click for more information.