Medically reviewed by Kristin Hall, FNP
Written by Our Editorial Team
Last updated 7/11/2022
Depression, anxiety and other forms of mental illness can have a real impact on your well-being and quality of life. They’re also remarkably common.
According to the National Survey on Drug Use and Health and the National Comorbidity Study Replication, an estimated 10.5 percent of all US women suffer from a depressive episode each year, with 23.4 percent affected by an anxiety disorder.
If you’ve been diagnosed with major depression or an anxiety disorder, your healthcare provider may prescribe an antidepressant such as Prozac® or Lexapro®.
Prozac and Lexapro both work by increasing your levels of certain natural chemicals that control your moods and feelings. It’s normal to switch antidepressants, and if Prozac isn’t quite the right medication for you, your healthcare provider may recommend switching to Lexapro.
Switching medications isn’t difficult, but it’s important to make the switch the right way to reduce your risk of experiencing side effects, drug interactions or withdrawal symptoms.
Below, we’ve talked about what Prozac and Lexapro are, as well as how they work to control the symptoms of depression and anxiety.
We’ve also covered everything you need to know about switching from Prozac to Lexapro, from common switching techniques to potential side effects that you should be aware of.
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 type of naturally-occurring chemical called a neurotransmitter. It’s one of several neurotransmitters that play a role in regulating your moods and feelings, including anxiety and happiness.
Low levels of serotonin are associated with several mental health issues, including depression, anxiety, obsessive-compulsive disorder and suicidal ideation.
Currently, Prozac is approved by the FDA to treat the following conditions:
Major depressive disorder (MDD)
Obsessive-compulsive disorder (OCD)
Panic disorder (PD)
In addition, Prozac is often prescribed off-label to treat other conditions, including social anxiety disorder (SAD, or social phobia), borderline personality disorder (BPD), Raynaud phenomenon, post-traumatic stress disorder and selective mutism.
Our detailed guide to Prozac offers 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 levels in your brain and body.
Currently, Lexapro is approved by the FDA to treat the following conditions:
Major depressive disorder
Generalized anxiety disorder
Our complete guide to Lexapro goes into more detail about how Lexapro works, what it’s used to treat, its adverse effects and more.
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 medications isn’t something to feel concerned about, nor is it a sign that your anxiety or depression can’t be treated. Instead, think of it as a step towards finding the right type of medication for your specific symptoms and needs as an individual.
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, after which you may notice improvements in your feelings, moods, sleep habits, appetite and other common symptoms of depression.
However, Prozac doesn’t work for everyone. If you have depressive symptoms that don’t improve after using Prozac for several weeks, you may get better results by switching to Lexapro or another type of antidepressant.
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 between different medications.
If you have persistent or bothersome side effects from Prozac, changing antidepressants may help to reduce their severity and improve your quality of life.
You have a condition that Prozac may not treat effectively. Certain anxiety disorders, such as 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.
In addition to Lexapro, several other types of antidepressants are also used to treat depression and anxiety disorders. These include:
Other selective serotonin reuptake inhibitors (SSRIs). These medications, including citalopram (the active ingredient in Celexa®), paroxetine (Paxil®) and sertraline (Zoloft®) also work by increasing serotonin levels.
Tricyclic antidepressants (TCAs). These older antidepressants typically aren’t used as first-line treatments for depression. However, your healthcare 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. However, your healthcare provider may prescribe an MAOI if newer antidepressants are unsuccessful for you.
Other antidepressants. Your healthcare provider may prescribe other antidepressants, such as bupropion (Wellbutrin®), if you have persistent side effects from SSRIs or other modern depression 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 are used to switch antidepressants, including gradually tapering your dosage, cross-tapering and switching directly to your new medication.
Tapering your dosage involves gradually reducing your dosage of Prozac, then giving your body time to complete a “washout” period of several days. 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 dosage of Prozac, then wait for seven days before starting treatment with Lexapro. If you take Prozac at a low dose (for example, less than 40mg per 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, aches, sweating and lethargy
Insomnia and other sleep-related issues, such as 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 treatment, and can range from mild to moderate in severity.
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.
Common side effects of Prozac include:
Asthenia (physical weakness)
Pharyngitis (sore throat)
Prozac can cause sexual side effects, which are 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).
Common side effects of Lexapro include:
Rhinitis (nasal congestion)
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 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 a group of potentially serious symptoms referred to as serotonin syndrome.
Serotonin syndrome occurs when your serotonin levels are too high. It can potentially cause a serious reaction that may be life-threatening.
Symptoms of serotonin syndrome include:
Elevated body temperature
Tachycardia (rapid heart rate)
Hypertension (high blood pressure)
Involuntary muscle jerking
Overly responsive reflexes
Hyperactive bowel sounds
Uncontrolled eye movement
Severe serotonin syndrome can cause delirium, muscle rigidity, seizures, renal failure, a body temperature of 106°F or higher, blood clotting, coma, respiratory distress and, in some cases, even death.
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 important 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 cause serotonin syndrome include:
Tricyclic antidepressants (TCAs)
Monoamine oxidase inhibitors (MAOIs)
Tramadol, fentanyl and other opioid pain drugs
Buspirone and other anxiety medications
St John’s wort
Prozac and Lexapro are both effective, popular medications for treating depression and certain forms of anxiety.
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 healthcare provider may suggest making the switch from Prozac to Lexapro or a similar medication.
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 a full range of depression and anxiety medications online, as well as mental health services such as individual therapy and anonymous online support groups.
You can also learn more about overcoming depression, anxiety, stress and other mental health concerns with our free mental health resources and content.