Lexapro Side Effects During First Week: What To Expect

By Andrew Yocum, MD
Medically reviewed checkmarkMedically reviewed
March 30, 2022

If a healthcare provider suggests you take an antidepressant like Lexapro, it’s natural to have some questions.

You want to be sure this is the right medication for you, based on your diagnosis and lifestyle.

You may also wonder what you should expect to experience from both short- and long-term use of the prescription medication.

Always ask your doctor about any treatment they recommend.

For extra help, this article will address what to expect the first week of taking Lexapro.

We’ll first cover what Lexapro is, what it’s used for, and how it works.

Then we’ll discuss the most common side effects of Lexapro, particularly in the first week of use.

Lastly, we’ll dive into typical dosages, what to do if you experience an overdose, and precautions when taking Lexapro.

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What Is Lexapro?

Lexapro is the brand name for the antidepressant medication escitalopram.

It belongs to the class of drugs called selective serotonin reuptake inhibitors (SSRIs).

This type of antidepressant medication is most commonly used for treating symptoms of clinical depression in people ages 12 and older and anxiety in adults.

Lexapro uses

Lexapro is approved to treat major depressive disorder and generalized anxiety disorder.

Doctors also prescribe Lexapro off-label to treat obsessive-compulsive disorder (OCD), panic disorder, premenstrual dysphoric disorder, post-traumatic stress disorder (PTSD), and some eating disorders.

How Lexapro works

Lexapro and other SSRI medications work to increase the amount of serotonin in your brain and body by blocking the regular cycle of serotonin reuptake in the brain.

This causes serotonin to stay in your system longer.

The process of increasing the amount of serotonin in your brain affects your sleep, metabolism, mood, and emotional regulation.

This helps people who have symptoms that affect their ability to eat, sleep, respond to their environment appropriately, and feel pleasure in their daily life.

A study comparing Lexapro with the generic version of escitalopram found that both medications were equally effective as initial treatments for moderate to severe major depression.

Side Effects of Lexapro

Almost every medication comes with possible side effects.

Which side effects and how mild or severe those side effects are differs from person to person depending on how a specific drug interacts with their body and brain.

Lexapro side effects are similar to those associated with other SSRIs and antidepressants.

In many cases, symptoms are most prominent for the first 1-2 weeks of treatment.

After that, typically many symptoms subside.

Common side effects in the first week

The most common side effects for the first week of taking Lexapro include:

Lexapro is also known to sometimes cause weight gain in patients. Other antidepressants may cause weight loss.

Serious side effects

There is potential for more serious side effects when taking Lexapro for the first time.

The following are some of the risks of taking Lexapro:

  • Serotonin syndrome: When your body has too much serotonin running through it, you can experience shivering, diarrhea, confusion, severe muscle tightness, fever, and even seizures. Serotonin syndrome is a medical crisis. Call 911 for immediate medical attention if your symptoms fit the description.
  • Sexual side effects: Adverse effects related to sexual function (such as delayed ejaculation or difficulty reaching orgasm) typically continue the entire time you take Lexapro. These effects can be significant enough to discuss changing your medication with your doctor.
  • Suicidal thoughts: Lexapro comes with an increased risk of suicide. If you or a loved one is starting Lexapro and you notice any suicidal thoughts or concerning changes in behavior, contact your doctor or the National Suicide Prevention Lifeline at 800-273-8255.
  • Mania episodes: Use Lexapro with caution if you have a history of bipolar disorder or manic episodes. Lexapro can sometimes cause episodes of mania, especially for patients with undiagnosed bipolar disorder.
  • Panic attacks: Common symptoms of a panic attack include chest pain, shortness of breath, hyperventilation, trembling or shakiness, nausea, and sweating. If you start experiencing panic attacks while taking Lexapro, speak with your doctor for medical advice about changing your medication.

Lexapro Dosage

The typical dosage of Lexapro to treat depression is 10 milligrams (mg) daily to start treatment.

Depending on how an individual responds, doctors may increase the dosage to 20 mg daily.

When using Lexapro to treat anxiety in adults, the typical dosage is also 10 mg taken once a day.

What if I miss a dose?

If you miss a dose of Lexapro, take that dose as soon as possible.

However, if it’s within a few hours of your regular dose time, skip the dose.

Never take two doses at once and never take more than prescribed by your doctor.

What if I overdose?

An overdose is a medical emergency.

Call 911 immediately. You can also call the poison control center at 1-800-222-1222 for guidance.

Overdosing on Lexapro can result in the following symptoms:

  • Convulsions
  • Coma
  • Dizziness
  • Insomnia
  • Nausea
  • Vomiting
  • Hypotension (low blood pressure)
  • Sinus tachycardia (sudden racing heart)
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Lexapro Precautions

Discuss any current medications (including supplements and herbal remedies) and your medical history with your doctor before starting Lexapro.

It is especially dangerous to switch to Lexapro within two weeks of taking any monoamine oxidase inhibitors (MAOIs). 

Other common interactions that can prevent effective or safe treatment with Lexapro include:

  • Pimozide
  • Alcohol
  • Stimulant medicines
  • Blood thinners
  • Opioids
  • Other serotonergic agents

If you have any known hypersensitivity to escitalopram or citalopram (Celexa), avoid taking Lexapro.

If you become pregnant while taking Lexapro, schedule a conversation with your doctor as soon as possible.

Lexapro can cause complications in pregnancy but the benefits of taking Lexapro may outweigh the risks involved. Your doctor can help you make an informed decision.

How K Health Can Help

Have more questions about using Lexapro? It will help to speak to a healthcare provider. 

Did you know you can get affordable primary care with the K Health app?

Download K to check your symptoms, explore conditions and treatments, and if needed text with a doctor in minutes. K Health’s AI-powered app is HIPAA compliant and based on 20 years of clinical data.

Frequently Asked Questions

Does Lexapro make you feel worse at first?
Due to side effects during the first few weeks of treatment, some say that Lexapro can make you feel worse at first. Side effects usually start to subside after about two weeks, so know that feeling “worse” doesn’t last very long.
How long do initial Lexapro side effects last?
Most side effects from starting Lexapro typically start to abate after two weeks. If any side effects continue longer than that and negatively impact your life, talk to your doctor. They may recommend another medication.
How long does it take to adjust to taking Lexapro?
It can take an average of four weeks to adjust to taking Lexapro. All bodies react differently. You may notice the effects of Lexapro within a day, or it could take up to six weeks. Most patients report that initial side effects go away after two weeks.

K Health articles are all written and reviewed by MDs, PhDs, NPs, or PharmDs and are for informational purposes only. This information does not constitute and should not be relied on for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment.

Andrew Yocum, MD

Dr Andrew Yocum is a board certified emergency physician. He graduated Summa Cum Laude from Kent State University with a Bachelor of Science in Molecular Biology before attending Northeast Ohio Medical University where he would earn his Medical Doctorate (MD).