Switching From Prozac to Lexapro

If you’ve been diagnosed with major depression or an anxiety disorder, your healthcare provider may prescribe an antidepressant such as Prozac® or Lexapro®. It’s normal to change antidepressants, and if Prozac isn’t quite the right medication for you, your provider might recommend switching from Prozac to Lexapro.

Changing medications isn’t necessarily difficult, but it’s important to make the transition properly to reduce your risk of side effects, drug interactions, or withdrawal symptoms.

Below, we’ll talk about what Prozac and Lexapro are, as well as how they work to control the symptoms of depression and anxiety.

We’ll also cover everything you need to know about switching from Prozac to Lexapro, from common switching techniques to potential side effects you should be aware of.

No. Prozac and Lexapro both increase the activity of certain brain chemicals that control moods and feelings. But while these antidepressant medications work similarly, they aren’t exactly the same.

Let’s unpack each medication.

Prozac is a prescription antidepressant that contains the active ingredient fluoxetine. It belongs to a class of antidepressants called selective serotonin reuptake inhibitors (SSRIs), which work by increasing the availability of serotonin in your brain and body.

Serotonin is a naturally occurring chemical called a neurotransmitter. It’s one of several neurotransmitters that play a role in regulating moods and feelings, including anxiety and happiness.

Low levels of serotonin activity are associated with various mental health issues, including depression, anxiety, obsessive-compulsive disorder (OCD), and even suicidal ideation.

Currently, Prozac is approved by the FDA (U.S. Food and Drug Administration) to treat these conditions:

• Major depressive disorder (MDD)

• Obsessive-compulsive disorder

• Panic disorder

• Bulimia nervosa

Prozac is also often prescribed off-label to treat other medical conditions, including:

• Premenstrual dysphoric disorder (PMDD)

• Social anxiety disorder (aka social phobia)

• Raynaud phenomenon (decreased blood flow to the fingers)

• Post-traumatic stress disorder (PTSD)

• Selective mutism (being unable to talk in specific situations)

Off-label use means a medication is prescribed to treat something the FDA hasn’t approved it for.

Our detailed guide to Prozac has more information about how Prozac works, what it’s used to treat, potential side effects, and more.

Lexapro is a prescription antidepressant that contains the active ingredient escitalopram. Much like Prozac, it’s a selective serotonin reuptake inhibitor that works by increasing serotonin activity in the brain and body.

Currently, Lexapro is approved by the FDA to treat:

• Major depressive disorder

• Generalized anxiety disorder (GAD)

Again like Prozac, Lexapro is also sometimes prescribed off-label for similar conditions like social anxiety disorder, OCD, panic disorder, PTSD, and PMDD.

Our complete guide to Lexapro goes into more detail about how Lexapro works, what it’s used to treat, and its adverse effects.

Changing antidepressants is a normal part of treating depression and anxiety. Many people try several antidepressants before finding one that improves their symptoms without bothersome or persistent side effects.

As such, switching meds isn’t something to feel concerned about — nor is it a sign your anxiety or depression can’t be treated. Think of it as getting one step closer to finding the right type of medication for your specific symptoms and unique needs.

Your healthcare provider may suggest switching from Prozac to Lexapro if:

• You have persistent symptoms that don’t improve with Prozac. Prozac can take two to four weeks to start working before you notice improvements in your feelings, moods, sleep habits, appetite, and outlook on life. But it doesn’t work for everyone. If you have depressive symptoms that don’t improve after several weeks on Prozac, you may get better results with another antidepressant like Lexapro.

• You have concerning or persistent side effects from Prozac. All antidepressants can cause adverse effects, but the rate of specific side effects can vary significantly among medications. If you have persistent or bothersome side effects from Prozac, changing antidepressants may help reduce their severity and improve your quality of life.

• You have a condition Prozac may not treat effectively. Certain anxiety disorders, like generalized anxiety disorder, aren’t on the approved indications list for Prozac or generic fluoxetine. If you have a form of anxiety or depression that’s better treated by another medication, it may be best to switch from Prozac.

Beyond Lexapro, several other types of antidepressants are used to treat depression and anxiety disorders. These include:

• Other selective serotonin reuptake inhibitors (SSRIs). These medications also work by increasing serotonin activity. Other SSRIs include citalopram (Celexa®), paroxetine (Paxil®), sertraline (Zoloft®), and fluvoxamine (Luvox®).

• Serotonin-norepinephrine reuptake inhibitors (SNRIs). These antidepressants, such as duloxetine (Cymbalta®) and venlafaxine (Effexor®), increase serotonin and norepinephrine activity. Norepinephrine is another neurotransmitter that helps with mood regulation.

• Tricyclic antidepressants (TCAs). These older antidepressants — including clomipramine (Anafranil®) — typically aren’t used as first-line treatments for depression. However, your provider may prescribe a tricyclic antidepressant if Prozac, Lexapro, and similar medications aren’t effective.

• Monoamine oxidase inhibitors (MAOIs). These older antidepressants are rarely used due to their risk of side effects and drug interactions. But your healthcare provider may prescribe an MAOI if newer antidepressants are unsuccessful for you.

• Other antidepressants. Your medical provider might prescribe other antidepressants, such as bupropion (Wellbutrin®) or mirtazapine (Remeron®). These are considered “atypical antidepressants” because they don’t neatly fit within another category. Unlike tricyclics and MAOIs, these atypical antidepressants are often used as first-line treatments.

Our guide to depression medications goes into more detail about how these medications work, as well as the key advantages of each class of antidepressants. 

Several different methods can be used to switch antidepressants, including gradually tapering your dosage, cross-tapering, or doing a direct switch to your new medication.

Tapering involves gradually reducing your dosage of Prozac, then giving your body time to complete a “washout period” of several days (when you aren’t taking any medication). The new antidepressant is then started at a low to moderate dose, which may be adjusted over time.

It’s common to gradually taper your Prozac dosage and wait seven days before starting treatment with Lexapro. If you take Prozac at a low dose (for example, less than 40 milligrams a day), your healthcare provider may instead suggest stopping Prozac without tapering your dosage.

Other methods of switching medications, such as switching medications directly or performing a cross-taper switch, generally aren’t used with Prozac and Lexapro.

It’s important not to stop Prozac or switch to a new antidepressant suddenly without first talking to your healthcare provider.

Stopping Prozac abruptly may cause antidepressant discontinuation syndrome, which can involve withdrawal symptoms, including:

• Flu-like symptoms, such as fatigue, headache, body aches, sweating, and lethargy

• Insomnia and other sleep-related issues, like vivid dreams and nightmares

• Balance issues, including light-headedness, dizziness, and vertigo

• Sensory disturbances, such as burning, shock-like sensations, and tingling

• Hyperarousal symptoms, such as irritability, agitation, anxiety, and jerkiness

These symptoms generally start within two to four days of abruptly stopping antidepressant treatment and can range from mild to moderate in severity. They can be uncomfortable, but they’re not dangerous. There’s no medical risk associated with them, and they go away as your body adjusts.

Make sure to closely follow your healthcare provider’s instructions when switching from Prozac to Lexapro. Let them know if you have any questions, need help reducing your dosage, or have any side effects or withdrawal symptoms during the switching process.

Like all antidepressants, Prozac and Lexapro can both cause side effects. Most side effects of Prozac and Lexapro are mild and tend to resolve on their own, although some may be severe, persistent, or bothersome.

Side effects of Prozac include:

• Nausea

• Diarrhea or dyspepsia (indigestion)

• Nervousness or anxiety

• Drowsiness and yawning

• Abnormal dreams

• Insomnia or trouble sleeping

• Asthenia (physical weakness)

• Dry mouth

• Weight gain or weight loss

• Sweating and tremors

• Rash

• Vasodilation (widening blood vessels)

Prozac can cause sexual side effects, commonly referred to as SSRI-induced sexual dysfunction. These include a reduced sex drive, difficulty reaching orgasm, and, in men, slow or difficult ejaculation and erectile dysfunction (ED).

Side effects of Lexapro include:

• Nausea or diarrhea

• Indigestion, constipation, or abdominal pain

• Insomnia

• Fatigue or somnolence (drowsiness)

• Dry mouth

• Dizziness

• Reduced appetite

• Weight gain or weight loss

• Sweating

Like Prozac, Lexapro can also cause sexual side effects, including a reduced level of interest in sex, difficulty reaching orgasm, and male sexual performance issues.

Prozac and Lexapro Serotonin Syndrome

Prozac and Lexapro both have the potential to interact with other medications and supplements, including other substances that increase serotonin levels. In some cases, these interactions can cause potentially serious symptoms called serotonin syndrome.

Serotonin syndrome happens when serotonin levels are too high. It can potentially cause a severe adverse reaction that may be life-threatening.

Symptoms of serotonin syndrome include:

• Elevated body temperature, excessive sweating, and shivering

• Tachycardia (rapid heart rate) or hypertension (high blood pressure)

• Involuntary muscle jerking, overly responsive reflexes, and tremors

• Dilated pupils and uncontrolled eye movement

• Hyperactive bowel sounds

• Increased alertness

• Pressured speech

Severe serotonin syndrome can cause:

• Delirium

• Muscle rigidity

• Seizures

• Renal failure

• A body temperature of 106°F or higher

• Blood clotting

• Respiratory distress

• Coma

In some cases, it can be fatal. Make sure to tell your healthcare provider if you notice any signs of serotonin syndrome while switching medications. Seek urgent medical care if you experience any severe side effects.

To reduce your risk of developing serotonin syndrome, it’s vital to inform your healthcare provider about all medications you currently use or have used within the past 14 days.

Medications and dietary supplements that may contribute to serotonin syndrome include:

• Tricyclic antidepressants (TCAs)

• Monoamine oxidase inhibitors (MAOIs)

• Other antidepressants

• Tramadol, fentanyl, and other opioid pain drugs

• Buspirone and other anxiety medications

• Amphetamines

• Lithium

• Tryptophan

• St. John’s wort

Let your healthcare provider know if you’re taking any of these other medications or supplements, and follow their medical advice. In many cases, some of these medications can be safely combined with Prozac or Lexapro, but it requires closer monitoring.

According to one national survey, roughly 10 percent of women in the U.S. suffer from a depressive episode each year, with about 23 percent affected by an anxiety disorder.

Prozac and Lexapro are both effective, popular medications for treating depression and certain forms of anxiety.

Here’s what to remember if you’re considering switching from Prozac to Lexapro:

• Lexapro and Prozac are both SSRIs. They work by increasing serotonin in the brain and body.

• They have different active ingredients and are FDA-approved to treat different conditions. Prozac is approved to treat MDD, OCD, panic disorder, and bulimia, while Lexapro is approved to treat major depressive disorder and generalized anxiety disorder.

• It’s common and normal to switch antidepressants. If Prozac isn’t working for you, or if you have side effects that don’t seem to improve over time, your provider may suggest making the switch from Prozac to Lexapro or another medication.

• Consult a healthcare professional. Make sure to closely follow your healthcare provider’s instructions when switching medications, and let them know if you experience any side effects or withdrawal symptoms.

Interested in getting help for depression, anxiety, or other mental health issues? We offer access to a range of depression and anxiety medications online for those who may benefit from them.

This article is for informational purposes only and does not constitute medical advice. The information contained herein is not a substitute for and should never be relied upon for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment. Learn more about our editorial standards here.