Lexapro Side Effects: Why Your Brain Is Reacting & Medically Approved Steps

If you've started Lexapro (generic name: escitalopram) and you're noticing changes in how you feel, you're not alone. Lexapro is one of the most commonly prescribed medications for anxiety and depression. It's generally well tolerated, but like all medications, it can cause side effects.

Understanding why these side effects happen can make them less alarming—and help you know what to do next.

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What Is Lexapro and How Does It Work?

Lexapro is a type of antidepressant called a Selective Serotonin Reuptake Inhibitor (SSRI).

Serotonin is a chemical messenger in your brain that helps regulate:

• Mood
• Anxiety
• Sleep
• Appetite
• Sexual function

Lexapro works by increasing the availability of serotonin in the brain. It does this by blocking its reabsorption (reuptake), allowing more serotonin to stay active between nerve cells.

This adjustment can improve mood and reduce anxiety—but it also temporarily disrupts your brain's balance while your body adapts. That adjustment period is where most side effects come from.

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Common Lexapro Side Effects

Most side effects are mild and improve within 1–3 weeks as your body adjusts.

1. Nausea

This is one of the most common early side effects.

Why it happens:
Serotonin isn't just in your brain—it's also in your digestive tract. Increasing serotonin can temporarily upset your stomach.

What helps:

• Taking Lexapro with food
• Starting at a lower dose
• Staying hydrated

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2. Headache

Headaches may occur in the first few weeks.

Why it happens:
Changes in serotonin can affect blood vessel regulation and pain perception.

What helps:

• Adequate hydration
• Gentle rest
• Over-the-counter pain relievers (if approved by your doctor)

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3. Increased Anxiety (at First)

It may sound strange, but some people feel more anxious during the first 1–2 weeks.

Why it happens:
Serotonin changes occur quickly, but the calming effects on mood circuits take longer. This temporary imbalance can cause jitteriness or restlessness.

Important: This usually settles within a couple of weeks. If anxiety becomes intense, contact your doctor.

If you're experiencing heightened anxiety symptoms and want to understand what you're going through, Ubie's free AI-powered Anxiety Symptom Checker can help you identify and better understand your symptoms in just a few minutes.

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4. Sleep Changes

Lexapro may cause:

• Insomnia
• Drowsiness
• Vivid dreams

Why it happens:
Serotonin influences your sleep-wake cycle.

What helps:

• Taking it in the morning if it causes insomnia
• Taking it at night if it causes drowsiness
• Keeping a consistent sleep routine

Always ask your prescribing doctor before changing when you take it.

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5. Sexual Side Effects

This may include:

• Reduced libido
• Difficulty reaching orgasm
• Erectile dysfunction

Why it happens:
Serotonin can suppress dopamine and other pathways involved in sexual function.

This side effect can persist in some individuals but is often manageable by:

• Adjusting the dose
• Switching medications
• Adding another treatment

Do not stop Lexapro abruptly due to this—discuss options with your doctor.

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6. Weight Changes

Some people experience mild weight gain over time.

Why it happens:

• Appetite changes
• Mood improvement leading to normalized eating
• Metabolic shifts

Regular physical activity and balanced nutrition help reduce risk.

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Less Common but Serious Side Effects

While rare, some reactions require immediate medical attention.

1. Suicidal Thoughts (Especially in Younger Individuals)

In adolescents and young adults, antidepressants can slightly increase suicidal thoughts early in treatment.

Seek urgent medical care if you notice:

• New or worsening suicidal thoughts
• Severe mood swings
• Aggressive behavior
• Impulsive actions

This risk is highest in the first few weeks.

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2. Serotonin Syndrome (Rare but Serious)

This happens when serotonin levels become dangerously high.

Symptoms include:

• High fever
• Rapid heart rate
• Muscle stiffness
• Confusion
• Heavy sweating

This is a medical emergency. Seek immediate care if these occur.

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3. Severe Allergic Reaction

Seek emergency care for:

• Swelling of face or throat
• Trouble breathing
• Severe rash

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Why Your Brain Reacts the Way It Does

Your brain runs on balance.

When Lexapro increases serotonin levels, your brain must recalibrate:

• Receptors adjust
• Signaling pathways shift
• Hormone systems rebalance

This adaptation period is called neurochemical adjustment. For most people:

• Side effects peak in the first 1–2 weeks
• Gradually fade by weeks 3–4
• Full therapeutic benefit appears after 4–8 weeks

Patience is important—but persistent or severe side effects should always be discussed with your doctor.

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Medically Approved Steps to Manage Lexapro Side Effects

Here's what doctors commonly recommend:

✅ 1. Start Low, Go Slow

Beginning at a lower dose and gradually increasing helps minimize side effects.

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✅ 2. Give It Time

Mild side effects often resolve within a few weeks.

Unless symptoms are severe, stopping too early may prevent you from experiencing the benefits.

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✅ 3. Never Stop Abruptly

Stopping Lexapro suddenly can cause discontinuation symptoms, including:

• Dizziness
• Flu-like symptoms
• Irritability
• Brain "zaps"

Always taper under medical supervision.

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✅ 4. Track Your Symptoms

Keep a simple log:

• When symptoms started
• Severity
• Any triggers
• Improvements

This helps your doctor make precise adjustments.

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✅ 5. Address Lifestyle Factors

Medication works best when combined with:

• Regular exercise
• Consistent sleep
• Balanced nutrition
• Therapy or counseling

Medication treats brain chemistry—but coping skills strengthen long-term recovery.

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When to Speak to a Doctor Immediately

Contact a healthcare professional right away if you experience:

• Suicidal thoughts
• Severe agitation
• Chest pain
• High fever
• Confusion
• Fainting
• Severe allergic symptoms

These may be life-threatening and require urgent care.

Even if symptoms aren't severe but are distressing, speak to your prescribing provider. Adjustments can almost always be made.

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The Bottom Line

Lexapro is a widely used, evidence-based treatment for anxiety and depression. Most side effects are mild, temporary, and manageable. They occur because your brain is adjusting to increased serotonin levels—not because the medication is harming you.

However, serious side effects—while rare—must be taken seriously.

If you're uncertain whether what you're feeling is related to your medication or your underlying anxiety, you can use Ubie's free AI-powered Anxiety Symptom Checker to gain personalized insights about your symptoms and determine whether you should reach out to your doctor.

Most importantly:

• Do not stop Lexapro abruptly
• Do not ignore severe symptoms
• Speak to a doctor about anything that could be serious or life-threatening

With proper guidance, most people tolerate Lexapro well and experience meaningful improvement in their quality of life.

If something feels off, reach out. You deserve safe, informed care.