Duloxetin

Duloxetin, also spelled duloxetine in many languages, is a prescription medication in the serotonin-norepinephrine reuptake inhibitor (SNRI) class. It increases the levels of serotonin and norepinephrine in the central nervous system by blocking their reuptake, with additional, smaller effects on other neurotransmitters. This mechanism underpins its use in mood disorders and certain types of chronic pain.

Common medical uses include major depressive disorder, and in some regions generalized anxiety disorder. It is also approved for diabetic peripheral neuropathic pain, fibromyalgia, and chronic musculoskeletal pain such as low back pain or osteoarthritis. Dosing and approved indications vary by country and condition; typical regimens begin with a low daily dose and may be adjusted based on response and tolerability, with maximum daily doses differing by indication.

Duloxetin is usually taken once daily, with or without food. Dose adjustments are necessary for hepatic or severe renal impairment, and it should be used with caution in older adults. It is not recommended for use with monoamine oxidase inhibitors and requires a washout period when switching to or from other serotonergic medications to reduce the risk of serotonin syndrome. Caution is advised in pregnancy and breastfeeding, and the drug can cause withdrawal symptoms if abruptly discontinued.

Common adverse effects include nausea, dry mouth, fatigue, sleep disturbance, dizziness, constipation, and decreased appetite. Some patients may experience increased sweating, blurred vision, or elevated blood pressure. Serious but less common risks include liver injury, suicidality in young adults, and serotonin syndrome, especially with other serotonergic drugs or certain medical conditions.

Pharmacokinetic notes: duloxetine is well absorbed orally and extensively metabolized in the liver, with biliary and renal routes of elimination. Drug interactions can occur with strong inhibitors or inducers of related metabolic pathways, alcohol, and other antidepressants.