Both Celexa and Lexapro belong to the class of medicines called selective serotonin reuptake inhibitors (SSRIs) and are FDA approved to treat depression.

The main differences between Celexa and Lexapro are:

• Celexa is a branded version of citalopram and Lexapro is a branded version of escitalopram
• Citalopram is a mixture of two stereo-isomers: R-citalopram and S-citalopram. Stereo-isomers are compounds that have the same chemical formula but differ only in their arrangement of atoms. Escitalopram contains only one isomer, S-citalopram
• Lexapro is also FDA approved to treat generalized anxiety disorder. Both Celexa and Lexapro may be used off-label to treat other conditions
• Celexa is only available in tablet form whereas Lexapro is available in both tablet and liquid form
• The equivalent dose of Lexapro is approximately half of that of Celexa. This means the dosing range of Lexapro is 10-20 mg/day and the dosing range for Celexa is 20-40 mg/day. In elderly patients, the dosing range for Lexapro is reduced to 5-10 mg/day and for Celexa, 10-20 mg/day
• There are some differences in their side effects with Celexa being more likely at higher dosages to cause QT prolongation (an electrical disturbance in the heart that can trigger some arrhythmias). Lexapro is more likely to cause sleep problems and taste disturbances.
• There is some evidence that Lexapro may be more effective and tolerable than other SSRIs, including Celexa, in the treatment of depression
• Celexa is not recommended for patients with pre-existing heart problems such as bradycardia or congenital long QT syndrome, low potassium or magnesium levels, a recent MI, or with uncompensated heart failure
• Celexa was FDA approved in 1998 and Lexapro was FDA approved in 2002.

Because both drugs are SSRIs, they have many similarities, such as:

• They both work by preventing the reuptake of serotonin, a chemical in the brain that acts as a messenger between nerve cells. SSRIs increase levels of serotonin in the nerve synapse and this has been associated with a reduction in depressive symptoms
• Side effects, such as headache, nausea, vomiting, increased sweating, and dry mouth are common to both Celexa and Lexapro
• Both have been associated with withdrawal symptoms when discontinued
• Both are branded drugs; however, generics are available for each drug which makes costs similar
• Both are prescription medicines, and neither is a controlled drug
• The likelihood of interactions with other drugs (such as monoamine oxidase inhibitors, pimozide, tramadol, St John’s wort) is similar, but in general, both citalopram and escitalopram have few drug-drug interactions because of their low potential to inhibit hepatic enzymes.