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How Does Celexa Work?


Updated February 28, 2013

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

Citalopram, often sold under the brand name Celexa, is an SSRI. Known as second generation antidepressants, SSRIs, or selective serotonin reuptake inhibitors, are newer medications than monoamine oxidase inhibitors (MAOIs) or tricyclic antidepressants (TCAs). Although they are typically prescribed for depression, citalopram and other SSRIs are sometimes used in the treatment of phobias, particularly social phobia.

A chemical known as a neurotransmitter, serotonin carries electrical impulses between the brain's neurons. The brain normally reabsorbs serotonin very quickly. Celexa and other SSRIs slow down this process, allowing the serotonin to remain in the space between neurons, known as the synaptic gap, for longer periods of time. The serotonin then sends additional impulses to the waiting neuron.

Taking Citalopram

Citalopram is available in both liquid and tablet form. It is available only by prescription, and is offered in various strengths. Never change your dosage amount or schedule without your doctor's advice. If you miss a dose and it is close to time for the next, simply skip the missed dose. Never take extra medication to compensate.

Like all SSRIs, citalopram may take some weeks to work, and your doctor may adjust your prescription over time. Talk to your doctor about any concerns you have.

Drug Interactions

Do not use this medication until at least two weeks have elapsed since you last took any MAOI.

Citalopram interacts with a wide range of natural remedies. Check with your doctor before using citalopram with tryptophan, St. John's wort, or any other herbal or natural medication. Citalopram interacts with a variety of both over-the-counter and prescription drugs as well, including NSAID pain relievers, blood thinners, diuretics, migraine medications, stomach pills, antibiotics, medications for mood disorders, and numerous others. Give your doctor a complete list of all prescription, over-the-counter, and natural remedies you use. Do not add any new medications or remedies without asking your physician. Avoid alcohol and sedatives when taking citalopram.


Citalopram, like all medications, has the potential to cause side effects. Most side effects, such as sleep disturbances and gastrointestinal changes, are mild and often subside in a few weeks. Tell your doctor immediately if you experience more severe side effects such as chest pain, fever, fainting or muscle stiffness. If you are pregnant or breastfeeding, or plan to become pregnant, discuss the risks with your doctor.

Since 2005, the FDA has required all SSRIs to carry a "black box" warning for the increased risk of suicidal ideation and behavior in children. The warning was expanded in 2007 to include adults under the age of 25. These medications are common, and most people tolerate them well, but it is important to make an informed decision when deciding whether you or your child should take such medication. So speak with your (or your child's) doctor about the benefits and risks of citalopram, or any other SSRI.

If you have certain medical conditions, you could be at risk for complications when using citalopram. Heart rhythm problems, recent heart attack, mineral imbalance, liver disease and kidney disease are among the conditions that could cause problems. Provide your physician with a complete list of all current and past medical conditions before beginning treatment with citalopram.

SSRI Discontinuation Syndrome

All SSRIs, including citalopram, carry a risk for withdrawal symptoms, particularly when the medication is suddenly stopped. Although the dizziness, headaches and odd electrical sensations are not generally considered harmful, they are often uncomfortable and may be disorienting. To minimize the risk for withdrawal effects, taper off the medication gradually under your doctor's guidance.


Mayo Clinic. SSRIs. Retrieved February 27, 2013 from http://www.mayoclinic.com/health/ssris/MH00066

U.S. National Library of Medicine. Citalopram. Retrieved February 27, 2013 from http://www.ncbi.nlm.nih.gov/pubmedhealth/PMHT0009639/

Roy-Byrne MD, Peter. "SSRIs and Suicide Risk: A Concern for Adults, Too?" Journal Watch Psychiatry. March 9, 2005. Retrieved February 27, 2013 from http://psychiatry.jwatch.org/cgi/content/full/2005/309/1

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