Medically reviewed by Kristin Hall, FNP
Written by Our Editorial Team
Last updated 7/10/2022
Depression is one of the most common mood disorders, with an estimated 21 million adults, or 8.4 percent of the entire US adult population, affected by at least one major depressive episode each year.
If you’ve been diagnosed with major depression, your mental health provider will likely prescribe an antidepressant to reduce the severity of your depressive symptoms.
Paxil® and Lexapro® are two of the most widely used antidepressants. Both are highly effective at treating depression, although some people with depression may find that one medication is a better choice for their needs than the other.
If you’re prescribed Paxil and find that it isn’t right for you, your healthcare provider may suggest switching from Paxil to Lexapro.
Changing antidepressants is generally a straightforward process, although there are some small things you should be aware of before you get started.
Below, we’ve covered what Paxil and Lexapro are, as well as how they work to treat depression and other forms of mental illness. We’ve also explained why you may need to switch from Paxil to Lexapro.
Finally, we’ve covered everything you need to know about the process of switching medications, from tapering your dosage to avoiding side effects, interactions and withdrawal symptoms.
Paxil is an antidepressant medication that contains the active ingredient paroxetine. It’s part of a class of antidepressants called selective serotonin reuptake inhibitor medications, or SSRIs.
The FDA first approved Paxil as a treatment for depression in the early 1990s. Currently, it’s an approved treatment for major depressive disorder (MDD), as well as the following other mental health conditions:
Generalized anxiety disorder (GAD)
Obsessive-compulsive disorder (OCD)
Post-traumatic stress disorder (PTSD)
Social anxiety disorder (SAD)
Panic disorder (PD)
Like other medications, Paxil is also used off-label to treat certain conditions, such as separation anxiety, persistent depressive disorder, body dysmorphic disorder and postpartum depression.
In men, Paxil is also used as a long-term treatment for some sexual functioning issues, such as premature ejaculation.
Paxil works by increasing the amount of serotonin that’s active in your brain and body. Serotonin is a type of naturally-occurring chemical referred to as a neurotransmitter, which acts by carrying chemical signals between your body’s nerve cells.
Serotonin is involved in regulating your feelings and moods, including feelings of happiness and anxiety. Lower-than-normal levels of serotonin are associated with mental health issues such as depression, anxiety, obsessive-compulsive disorder and an elevated risk of suicidal ideation.
Experts believe that Paxil’s effects on serotonin produce its antidepressant effects, allowing it to reduce the severity of clinical depression symptoms and improve quality of life.
Our detailed guide to Paxil provides more information about how Paxil works, its uses, potential side effects and more.
Lexapro is an antidepressant that contains the active ingredient escitalopram. Like Paxil, it’s an SSRI that works by increasing serotonin levels in your brain and helping to stabilize your moods and feelings.
Currently, Lexapro is approved by the FDA to treat the following conditions:
Major depressive disorder
Generalized anxiety disorder
Our detailed guide to Lexapro provides more information about how Lexapro works, the mental health disorders it’s prescribed to treat, potential side effects and more.
Treating depression, anxiety or a related mental health condition can be a challenging process, and a key part of it is finding an antidepressant that improves your symptoms with manageable side effects.
It’s common and very normal to change antidepressants — often several times — as part of this process.
Your healthcare provider may recommend switching from Paxil to Lexapro if:
Paxil doesn’t produce improvements in your symptoms after several weeks. It can take two to four weeks for antidepressants to start working, but after this amount of time, you should be able to notice improvements in your depression symptoms.
If Paxil still isn’t effective for you after several weeks of consistent use, it may be best to switch to a more suitable medication.
You have severe and/or persistent side effects from Paxil. Paxil can cause adverse effects, including nausea, dizziness, anxiety and difficulty sleeping. Many of these side effects are mild and transient, although some may be severe and/or persistent.
Because side effect rates can differ between antidepressants, your healthcare provider may recommend switching medications if you have side effects from Paxil that don’t get better over time.
Switching antidepressants generally isn’t difficult, but it can be more complex than just stopping one medication and replacing it with another.
When you abruptly stop taking an antidepressant, or switch from one drug to another, there’s a risk of developing antidepressant withdrawal syndrome — a withdrawal reaction that happens in response to the sudden discontinuation of your medication.
Antidepressant discontinuation affects around 20 percent of antidepressant users who abruptly stop taking their medication. Discontinuation symptoms can include flu-like symptoms, nausea, balance issues, sensory disturbances and hyperarousal symptoms, such as agitation.
To reduce your risk of developing antidepressant discontinuation symptoms after stopping Paxil, your healthcare provider will recommend using a medication switching technique.
Several techniques are used to switch antidepressants, including the following:
Tapered switch. This technique involves gradually reducing your dosage of medication, then stopping for a “washout” period. The new antidepressant is then started at a low to moderate dose, which may be adjusted over time.
Several techniques are used as part of the tapered switching process, including a slower conservative switch and a faster moderate switch.
Cross-taper switch. This technique involves gradually tapering the dosage of your first medication while simultaneously increasing your dosage of the new medication. Using a cross-taper approach allows you to switch medications faster.
Direct switch. This technique involves stopping your first medication without performing a taper, then starting the new medication the next day. This approach is only suitable for some people and cannot be used with all antidepressants.
When switching from Paxil to Lexapro, the most appropriate approach is to taper your dosage of Paxil, then start treatment with Lexapro at a low dose.
As you adjust to Lexapro, your healthcare provider may gradually increase your dosage. Finding the optimal dose of Lexapro for your symptoms can take time, and it may be necessary to adjust your dosage several times until you achieve the right outcome.
As part of the process of changing from Paxil to Lexapro, your healthcare provider may suggest completing a brief washout period (typically two to five days) between cessation of Paxil and the start of treatment with Lexapro.
This washout period helps to completely eliminate any remaining Paxil from your body. This can reduce your risk of drug interactions, which may occur when several antidepressants are active in your body at the same time.
When switching medications, make sure to closely follow your healthcare provider’s instructions and let them know if you notice any side effects or signs of a potential drug interaction.
To learn about Lexapro and another common antidepressant, read our blog on switching from Celexa to Lexapro.
Paxil and Lexapro can both cause side effects. Most side effects of these medications are mild and transient, meaning they’ll improve gradually over time. However, some side effects of Paxil or Lexapro may be long-lasting and more severe.
Common side effects of Paxil include:
Asthenia (physical weakness)
Loss of appetite
Paxil can also cause or contribute to sexual dysfunction, including reduced libido and difficulty reaching orgasm. In men, Paxil may cause erectile dysfunction (ED) and abnormal ejaculation.
Common side effects of Lexapro include:
Like Paxil, Lexapro may cause sexual side effects including a decreased level of interest in sex, difficulty reaching orgasm and other sexual performance issues.
Both Paxil and Lexapro can interact with other medications and dietary supplements, including common medications for depression, anxiety and pain. When used with other medications that increase serotonin levels, Paxil and Lexapro may cause serotonin syndrome.
Serotonin syndrome is a serious, potentially life-threatening syndrome that develops when your serotonin levels become too high. It can cause severe symptoms, including:
Hypertension (high blood pressure)
Tachycardia (rapid heart rate)
Elevated body temperature
Involuntary muscle jerking
Overly responsive reflexes
Hyperactive bowel sounds
Uncontrolled eye movement
When severe, serotonin syndrome can cause very high body temperatures in excess of 106°F, as well as delirium, muscle rigidity, seizures, renal failure, acute respiratory distress syndrome, intravascular clotting, coma and even death.
Medications and dietary supplements that may interact with Paxil or Lexapro and increase your risk of developing serotonin syndrome include:
Tricyclic antidepressants (TCAs)
Monoamine oxidase inhibitors (MAOIs)
Other types of antidepressants
Tramadol, fentanyl and other opioid pain medications
Buspirone and other medications for anxiety
St John’s wort
To reduce your risk of serotonin syndrome or other interactions, inform your healthcare provider about any over-the-counter medications, prescription medications or supplements you currently use or have used within the last 14 days before starting treatment with Paxil or Lexapro.
It’s also important to inform your healthcare provider as soon as possible if you notice any of the common symptoms of serotonin syndrome above while switching antidepressants.
Paxil and Lexapro are two common medications for treating depression. Because they’re part of the same drug class, switching from one to the other is usually a straightforward, simple process that can be completed in a short time frame.
When switching medications, your healthcare provider will likely instruct you to gradually reduce your dosage of Paxil, then switch to Lexapro.
Make sure to follow their instructions as closely as possible, and let them know if you notice any side effects or have any concerns about using your new medication.
Interested in seeking help for depression or anxiety? We offer a range of mental health services online, including online psychiatry and individual therapy.
You can also learn more about dealing with depression, anxiety, chronic stress and other mental health concerns using our free online mental health resources and content.