Lexapro (escitalopram) is an antidepressant that works by increasing serotonin levels in the brain. It’s one of the most commonly prescribed medications in a class called selective serotonin reuptake inhibitors, or SSRIs. The FDA has approved it for treating major depressive disorder in adults and adolescents aged 12 to 17, and generalized anxiety disorder in adults.
How Lexapro Works in the Brain
Your brain cells communicate by releasing chemical messengers into tiny gaps between neurons. One of those messengers, serotonin, plays a major role in regulating mood, sleep, and anxiety. Normally, after serotonin delivers its signal, a transporter protein on the sending neuron vacuums it back up for recycling. Lexapro blocks that transporter protein, which means serotonin stays active in the gap between neurons for longer. The result is a stronger, more sustained serotonin signal.
This is a targeted process. Unlike older antidepressants that affect multiple brain chemicals at once, Lexapro acts almost exclusively on serotonin. That selectivity is what gives SSRIs their generally milder side effect profile compared to earlier generations of antidepressants.
What Lexapro Treats
Lexapro has two FDA-approved uses. The first is major depressive disorder, where it’s approved for both adults and adolescents 12 and older. The second is generalized anxiety disorder in adults. It is not approved for children under 12 for any condition, and its safety in patients under 18 for anxiety specifically hasn’t been established.
Doctors also prescribe Lexapro off-label for other conditions, including social anxiety disorder, panic disorder, and obsessive-compulsive disorder. Off-label prescribing is common and legal, but it means the FDA hasn’t formally reviewed the drug for that specific use.
How Long It Takes to Work
Lexapro doesn’t work like a painkiller you take and feel within an hour. Most people begin noticing some improvement in the first one to two weeks, but full therapeutic effects for depression and generalized anxiety typically take four to six weeks. For social anxiety disorder, the timeline is slower: meaningful improvement often doesn’t become evident until around 12 weeks of treatment.
Early signs of improvement within the first week, even subtle ones, tend to predict a good response down the line. If you’ve been taking Lexapro for six to eight weeks without any change, that’s a reasonable point to talk with your prescriber about adjusting the dose or trying something different.
Typical Dosing
The standard starting dose is 10 mg once daily for both depression and generalized anxiety. You can take it in the morning or evening, with or without food. If 10 mg isn’t enough after at least one week, your prescriber may increase it to 20 mg. Clinical trials found that both 10 mg and 20 mg were effective for depression, and the higher dose didn’t consistently outperform the lower one. Elderly patients and people with liver problems generally stay at 10 mg.
Common Side Effects
In clinical trials for depression, the most frequently reported side effects compared to a sugar pill were nausea (15% vs. 7%), insomnia (9% vs. 4%), and drowsiness (6% vs. 2%). In anxiety trials, those numbers ran slightly higher: nausea affected 18% of patients, insomnia 12%, and drowsiness 13%. Most of these side effects are worst during the first week or two and then taper off as your body adjusts.
Sexual Side Effects
Sexual side effects are among the most common reasons people stop taking SSRIs, and they’re more prevalent than short-term trial data suggests. Longer-term studies estimate that 25% to 73% of people on SSRIs experience some form of sexual dysfunction, including reduced desire, difficulty with arousal, or trouble reaching orgasm. Men and women are affected at roughly similar rates (around 62% and 60%, respectively), though men tend to report more problems with desire specifically. These effects often persist for as long as you take the medication, which makes them worth discussing with your prescriber if they become bothersome.
Weight Changes
Weight gain from Lexapro is uncommon in the short term but becomes more likely with longer use. A large population study found that people taking antidepressants had a higher rate of gaining 5% or more of their body weight compared to people not on antidepressants. The increased risk was most noticeable in years two and three of treatment, then gradually declined. Roughly speaking, for every 27 patients treated for a year or more, one additional person experienced a meaningful weight gain episode that wouldn’t have happened otherwise.
Drug Interactions and Serotonin Syndrome
Because Lexapro raises serotonin levels, combining it with other substances that also boost serotonin can push levels dangerously high, a condition called serotonin syndrome. Symptoms include agitation, rapid heartbeat, high blood pressure, muscle twitching, and in severe cases, seizures.
The highest-risk combinations involve older antidepressants called MAOIs, which should never be taken with Lexapro. But the list of interacting substances is broader than many people realize:
- Other antidepressants, including SNRIs, tricyclics, and even some that affect serotonin indirectly
- Migraine medications called triptans
- Opioid pain medications, particularly tramadol and fentanyl
- Over-the-counter cough medicines containing dextromethorphan (the active ingredient in many cold and flu products)
- Supplements like St. John’s wort
- Recreational drugs including MDMA (ecstasy), cocaine, and LSD
Serotonin syndrome most often occurs when two serotonin-raising substances are combined, not from Lexapro alone. Still, it’s worth mentioning all supplements and medications you take, including over-the-counter products, to whoever prescribes your Lexapro.
What Happens When You Stop
Lexapro has a half-life of about 27 to 33 hours, meaning it takes roughly a day and a half for your body to clear half of each dose. But stopping abruptly after weeks or months of use can trigger discontinuation syndrome, sometimes called withdrawal, even though the drug isn’t addictive in the traditional sense.
Symptoms typically appear within a week of stopping and can include dizziness, nausea, headache, insomnia, vivid dreams, irritability, and a distinctive “brain zap” sensation that people describe as brief electric-shock feelings in the head. These symptoms are uncomfortable but not dangerous, and they usually resolve within one to three weeks.
The standard approach to avoiding this is a gradual taper. Most clinicians recommend reducing the dose by about 25% per week, though some patients need a slower schedule of six to eight weeks or even longer. If you’ve only been on Lexapro for four weeks or less, tapering is generally unnecessary. For people who have significant trouble discontinuing, switching temporarily to a longer-acting SSRI before stopping can smooth the process. The key point: don’t stop Lexapro cold turkey without a plan, and if withdrawal symptoms are severe, going back to your previous dose and tapering more slowly is a reasonable strategy.