Citalopram is used to treat depression. Citalopram is in a class of antidepressants called selective serotonin reuptake inhibitors (SSRIs). It works by increasing the amount of serotonin, a natural substance in the brain that helps maintain mental balance.
Citalopram comes as a tablet and a solution (liquid) to take by mouth. It is usually taken once a day, in the morning or in the evening, with or without food. Take citalopram at around the same time 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 citalopram exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.
Summary from MedlinePlus.gov, click for more information.