Missing a single dose of Lexapro is unlikely to cause serious problems, but you may notice some uncomfortable symptoms as your body adjusts to the temporary dip in medication levels. The standard advice: take the missed dose as soon as you remember, unless it’s close to the time for your next dose. In that case, skip it and continue your regular schedule. Never take two doses at once to make up for the one you missed.
What to Do When You Realize You Missed a Dose
If only a few hours have passed since your usual time, go ahead and take it. If you’re already approaching your next scheduled dose, skip the missed one entirely and pick back up on your normal routine. The key rule is simple: do not double up. Taking two doses close together raises the level of serotonin activity in your brain beyond what your body has adapted to, which can trigger a dangerous reaction called serotonin syndrome (more on that below).
There’s no precise hourly cutoff published for Lexapro specifically. A practical guideline: if you’re more than halfway to your next dose, it’s generally better to skip. So if you take Lexapro every morning at 8 a.m. and you remember at 6 p.m., you’re probably fine to take it. If you don’t remember until 2 a.m., skip it and take your normal dose in the morning.
Why One Missed Dose Usually Isn’t a Crisis
Lexapro (escitalopram) has a half-life of about 27 to 32 hours, meaning it takes roughly that long for your body to clear just half the drug from your system. After a single missed dose, a significant amount of the medication is still circulating. This relatively long half-life acts as a buffer, which is why one skipped dose rarely triggers full-blown withdrawal symptoms. By contrast, antidepressants with shorter half-lives can cause noticeable symptoms much faster.
It takes about one week of daily dosing for Lexapro to reach steady levels in your blood. Missing a single dose creates a small dip in those levels, but the reservoir built up over days of consistent use means your brain chemistry doesn’t shift dramatically overnight.
Symptoms You Might Notice
Even with that buffer, some people feel “off” after a missed dose. The symptoms resemble what clinicians call antidepressant discontinuation syndrome, a set of reactions that typically appear within two to four days of stopping an antidepressant. With a single missed dose, these effects tend to be milder, but sensitive individuals can notice them within a day or so. Escitalopram carries a moderate risk of discontinuation symptoms compared to other antidepressants.
Common physical symptoms include:
- Dizziness and lightheadedness
- Nausea, sometimes with vomiting
- Headache and general achiness
- Fatigue and sweating
- Tingling or burning sensations in the skin
On the emotional side, you might experience a noticeable uptick in anxiety, irritability, or agitation. Some people also report vivid or disturbing dreams the night after a missed dose.
Brain Zaps
One of the most distinctive and unsettling symptoms is what people call “brain zaps.” These feel like brief electrical jolts or buzzing sensations inside your head, sometimes accompanied by a whooshing sound or a split-second feeling of disorientation. Some people describe it as their brain briefly “rebooting.” Brain zaps are a type of nerve sensation caused by sudden shifts in serotonin availability between neurons. When the medication that was regulating serotonin levels dips, the balance gets disrupted, and these short, repetitive shocks can result. They’re not dangerous, but they can be alarming if you don’t know what’s happening.
Why You Should Never Double Up
The temptation to take two pills the next day to “catch up” is understandable, but it carries real risk. Doubling your dose spikes serotonin activity beyond what your body is calibrated for. This can trigger serotonin syndrome, a condition that ranges from uncomfortable to life-threatening.
Mild serotonin syndrome looks like agitation, restlessness, a racing heart, dilated pupils, heavy sweating, diarrhea, and muscle twitching. Severe cases can escalate to high fever, seizures, irregular heartbeat, and loss of consciousness. The risk is higher if you’re also taking other medications that affect serotonin, such as certain migraine drugs, pain medications, or supplements like St. John’s wort. If you accidentally take a double dose and start experiencing a rapid heartbeat, confusion, or muscle rigidity, seek emergency care.
What Happens If You Miss Several Days
Missing two or more consecutive doses is a different situation. With each passing day, your blood levels of Lexapro drop further, and the likelihood of discontinuation symptoms increases substantially. By day three or four without medication, many people experience the full range of withdrawal effects: flu-like symptoms, mood swings, brain zaps, sleep disruption, and significant anxiety or irritability.
If you’ve missed multiple days, don’t simply restart at your full dose without guidance. Depending on how long you’ve been off the medication and what dose you were taking, your prescriber may want you to resume at a lower dose and taper back up. This is especially true if you’ve been off Lexapro for a week or more. Contact your prescriber’s office or pharmacy for specific instructions based on your situation.
Staying Consistent With Your Dose
The most common reason people miss antidepressant doses is simply forgetting. Other frequent reasons include feeling better and assuming the medication is no longer needed, worrying about side effects, or struggling to take it at the same time each day. All of these are normal, but each missed dose chips away at the steady drug levels your brain has adapted to.
A few strategies that help:
- Pair it with a daily habit. Taking Lexapro alongside something you already do every day, like brushing your teeth or making coffee, creates a natural reminder.
- Use a phone alarm. A daily alarm set for the same time removes the need to remember on your own. Medication-tracking apps can also send reminders and let you log each dose.
- Use a pill organizer. A weekly pill case makes it immediately obvious whether you’ve taken today’s dose, which eliminates the “did I already take it?” uncertainty.
- Keep a backup dose accessible. If you travel or stay somewhere other than home regularly, keeping a small supply in your bag prevents missed doses due to logistics.
If you’re missing doses because you feel better, that’s actually a sign the medication is working. Lexapro doesn’t cure the underlying condition; it manages it. Stopping or becoming inconsistent often brings symptoms back, sometimes within days. If you want to explore reducing or stopping your medication, that’s a conversation to have with your prescriber, who can set up a gradual taper to minimize withdrawal effects.