Celexa is a selective serotonin reuptake inhibitor (SSRI) that blocks the reuptake of serotonin (5-HT) by the nerves of the central nervous system, which enhances serotonergic activity. Citalopram, sold under the brand name Celexa among others, is an antidepressant of the selective serotonin reuptake inhibitor (SSRI) class. [7][9] It is used to treat major depressive disorder, obsessive–compulsive disorder, panic disorder, and social anxiety disorder. [7] Overview: Citalopram is used to treat depression. It is thought to work by increasing the amount of a natural chemical called serotonin in the brain. Common side effects may include nausea, changes. Celexa (citalopram) is a brand-name drug that’s used to treat depression in adults. Celexa comes as a tablet that you swallow. Learn about side effects, dosage, uses, and more. Celexa (citalopram hydrobromide) used to treat the symptoms of depression. Learn side effects, dosage, drug interactions, warnings, patient labeling, reviews, and more. Take this medicine only as directed by your doctor, to benefit your condition as much as possible. Citalopram is a prescription medicine used in adults to treat depression. Citalopram is also used to treat major depressive disorder (MDD). Citalopram belongs to a class of antidepressants called selective serotonin reuptake inhibitors (SSRIs).