Lexapro (escitalopram) is a medication used to treat various forms of anxiety and depression-related disorders. It is available by prescription only and has a generic equivalent. It has a relatively long half-life compared to other drugs in its class.
The half-life of a drug is the time it takes for the peak level of the medication available in the bloodstream to be reduced to half its original strength. The level continues to decrease by half until it is no longer detectable in the blood as long as no additional doses are taken.
Lexapro's half-life is 27 to 32 hours. If you took a single dose of 20 mg, within 27 to 32 hours that original dose would be halved to 10 mg, then 27 to 32 hours later to 5 mg, and so on until it is out of your bloodstream.
Based on Lexapro's half-life, it would take roughly 4.5 to 5 days for Lexapro to be at undetectable levels in your bloodstream.
Withdrawal from Lexapro can lead to increased side effects thought to be related to its half-life. As the level of Lexapro decreases, the brain and central nervous system try to compensate, resulting in increased side effects.
Lexapro has an FDA black-box warning for suicidal behavior among adolescents. While this type of side effect can occur at any time during treatment, it is more likely to occur with increases or decreases in the dose or if the dose is stopped abruptly.