Lexapro is the brand name for escitalopram, a selective serotonin reuptake inhibitor (SSRI) used to treat anxiety and depression. It's one of the two SSRIs most commonly chosen as first-line treatment for generalized anxiety disorder, alongside sertraline. The therapeutic effect on anxiety develops over four to six weeks at a typical dose of 10 to 20 mg per day. Most patients tolerate it well.
What Lexapro is
Lexapro is the brand name for escitalopram, a medication in the SSRI class. Escitalopram is the active S-enantiomer of citalopram (Celexa). It was approved by the FDA in 2002 for major depressive disorder and in 2003 for generalized anxiety disorder. It's also widely used off-label for panic disorder, social anxiety disorder, and obsessive-compulsive disorder.
Generic escitalopram is available and is clinically equivalent to brand-name Lexapro. Most insurance plans cover the generic at low cost. Brand-name Lexapro is generally only prescribed when there's a specific tolerability difference noted with a particular generic manufacturer. The MedlinePlus drug information page for escitalopram is a good consumer-level reference.
For the underlying class mechanism and the broader picture of how SSRIs work for anxiety, see the longer reference: how CBT and SSRIs work for anxiety.
What it does
Escitalopram blocks the serotonin transporter (SERT), the protein that normally takes serotonin back into neurons after release. The immediate result is more serotonin available in the synapse. Over weeks, this sustained increase produces gradual changes in how the brain's threat-detection regions, particularly the amygdala and its prefrontal regulators, respond to potential threats. The underlying reactivity comes down. The baseline becomes quieter. To see this at the synapse, PsychiatryRx has an interactive guide to how SSRIs work.
This is why the biochemical effect (within hours of the first dose) and the clinical effect on anxiety (over four to six weeks) are on different timescales. Receptor adaptation, not the initial serotonin increase, is what produces the therapeutic change. Patients who expect to feel "calmer" in the first few days are usually disappointed. Patients who give the medication four to six weeks usually notice a real shift.
What it feels like
Patients on a working dose of Lexapro rarely describe feeling medicated in any direct way. The more common description is that the things that used to bother them bother them less. The space between trigger and reaction widens. Sleep often improves. The body feels less braced.
Early side effects in the first one to two weeks can include nausea, mild jitteriness, headaches, sleep disruption, and a temporary increase in anxiety. These tend to settle. Sexual side effects (reduced libido, delayed orgasm) are common, may persist for as long as the medication is taken, and are a frequent reason patients stop.
When it's chosen
Lexapro is often the first SSRI tried for generalized anxiety disorder for several reasons. It has a clean drug-interaction profile. It doesn't significantly inhibit the cytochrome P450 enzymes that metabolize many other medications, which matters in patients on multiple medications, particularly older adults. Its side effect profile is generally well-tolerated at standard doses. The dosing is simple, and it's FDA-approved for generalized anxiety, which makes coverage decisions easier.
For panic disorder, social anxiety disorder, and OCD, sertraline or paroxetine is sometimes preferred, but escitalopram has good evidence in each.
Typical dosing and timeline
Starting dose for anxiety is typically 5 mg or 10 mg daily, taken in the morning or evening. Many clinicians start at 5 mg for one week to reduce early side effects, then increase to 10 mg. The typical effective dose is 10 to 20 mg daily, and the FDA-approved maximum is 20 mg. Doses above 20 mg don't consistently produce additional benefit and may increase QT-prolongation risk.
The therapeutic effect on anxiety develops over four to six weeks at a stable dose. The honest framing during the first month: it's too early to judge whether the medication is working.
Side effects and cautions
Sexual side effects are the most common reason patients ask to switch. QT interval prolongation is a dose-related effect, uncommon at 10 mg and rare at 20 mg in patients without other risk factors, but combinations with other QT-prolonging medications can become clinically relevant. Sodium levels can drop on SSRIs, particularly in older adults. Bleeding risk is mildly increased, particularly with NSAIDs or anticoagulants.
The FDA boxed warning on increased risk of suicidal thoughts and behaviors in patients younger than 25 in the first few months of treatment applies. The absolute risk increase is small and is a reason for close monitoring, not a reason to avoid the medication. The NIMH overview of mental health medications discusses this in patient-facing language.
Discontinuation symptoms can occur if escitalopram is stopped abruptly: dizziness, electric-shock sensations, irritability, flu-like symptoms. These are usually avoidable with a gradual taper over several weeks.
What Lexapro doesn't do
Lexapro doesn't produce an immediate calming effect. Individual doses don't produce a felt change the way a benzodiazepine does. The therapeutic effect is the result of weeks of receptor adaptation, not the dose taken in the morning.
Lexapro doesn't address the cognitive patterns of anxiety in the way cognitive behavioral therapy does. Most patients benefit from combined treatment with therapy, particularly for panic disorder, social anxiety disorder, and OCD.
Lexapro isn't a controlled substance. It doesn't produce dependence in the addictive sense. It does produce physical adaptation, which is why it requires a gradual taper to stop.
Comparison with related medications
Both Lexapro and Zoloft are first-line SSRIs for anxiety. Lexapro is often slightly better tolerated in the first weeks; sertraline has slightly stronger evidence in panic disorder and PTSD. See the Lexapro vs Zoloft comparison for the detail.
Lexapro is the S-enantiomer of citalopram and has a slightly cleaner side-effect profile than the racemic form. Compared with Prozac (fluoxetine), Prozac has a much longer half-life, which makes discontinuation easier but can complicate switches.
Compared with venlafaxine (an SNRI, not an SSRI), Lexapro produces less norepinephrine effect and has a milder discontinuation syndrome. See the SNRIs reference for the SNRI class picture.