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Switching from Zoloft to Prozac: What to Expect

Mary Lucas, RN

Medically reviewed by Mary Lucas, RN

Written by Our Editorial Team

Last updated 12/09/2020

Zoloft® (sertraline) and Prozac® (fluoxetine) are two of the most common medications used to treat depression.

Both Zoloft and Prozac are selective serotonin reuptake inhibitors, or SSRIs. They work to treat depression and other mental health disorders by increasing the level of serotonin, an important neurotransmitter, in your brain.

If you’ve been diagnosed with depression, it’s common and normal to try different antidepressants before finding an effective treatment for your symptoms. If Zoloft isn’t an effective medication for you, your healthcare provider may recommend switching to Prozac.

Below, we’ve explained what you need to know if you’re switching from Zoloft to Prozac, from switching methods to potential side effects you may experience and more. 

Zoloft (Sertraline) and Prozac (Fluoxetine): An Overview

Zoloft, which contains the active ingredient sertraline, and Prozac, which contains fluoxetine, are two common prescription medications for depression. 

Zoloft is currently approved by the FDA as a treatment for depression, obsessive compulsive disorder (OCD), panic disorder, post-traumatic stress disorder (PTSD), social anxiety disorder (SAD) and premenstrual dysphoric disorder (PMDD).

Prozac is currently approved by the FDA as a treatment for depression, obsessive compulsive disorder (OCD), panic disorder and bulimia nervosa.

Like other SSRIs, both medications are used as first-line treatments for depression due to their safety, tolerability and effectiveness.

Although Zoloft and Prozac are both effective medications, it’s common and normal to have to change from one antidepressant to another. Research has found that only about 37 percent of people with depression experience remission after the first stage of treatment.

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How to Switch From Zoloft (Sertraline) to Prozac (Fluoxetine)

Several methods are used to switch SSRIs. For some antidepressants, it’s safe to switch from one medication to another immediately. For others, you may need to taper your dosage slowly and switch after several days or weeks.  

When switching from Zoloft to Prozac, the recommended approach is to taper your dosage of Zoloft (sertraline) until you stop using your medication. After completely stopping Zoloft, you’ll typically start using fluoxetine at a dosage of 10mg per day.

The tapering process involves gradually lowering your dosage very few days, typically over the course of approximately four weeks. Your healthcare provider will provide specific instructions to help you reduce your dosage of Zoloft in a safe, controlled manner. 

Based on your medical needs, your previous usage of antidepressants and other factors, your healthcare provider may suggest a faster or slower tapering process or prescribe Prozac at a higher or lower dosage. 

It’s important to follow your healthcare provider’s instructions carefully. Do not suddenly switch from one medication to another or stop taking your medication without tapering. Doing this can increase your risk of antidepressant discontinuation syndrome or drug interactions.

Side Effects of Zoloft and Prozac

As SSRIs, Zoloft (sertraline) and Prozac (fluoxetine) usually cause similar side effects. However, as these medications aren’t exactly the same, you may experience slightly different side effects after switching from Zoloft to Prozac.

According to data from clinical trials, the most common side effects of Zoloft are:

  • Diarrhea

  • Difficulty ejaculating

  • Dyspepsia (indigestion)

  • Hyperhidrosis (excessive sweating)

  • Nausea

  • Reduced appetite

  • Reduced libido

  • Tremor

The most common side effects of Prozac are 

  • Abnormal dreams

  • Abnormal ejaculation

  • Anorexia

  • Anxiety

  • Asthenia (physical weakness)

  • Diarrhea

  • Dry mouth

  • Dyspepsia (indigestion)

  • Flu syndrome

  • Impotence (erectile dysfunction)

  • Insomnia

  • Decreased libido

  • Nausea

  • Nervousness

  • Pharyngitis (sore throat)

  • Rash

  • Sinusitis

  • Somnolence (sleepiness)

  • Sweating

  • Tremor

  • Vasodilation (widening of blood vessels which can cause a drop in your blood pressure)

  • Yawning

If you experience any unpleasant or persistent side effects after switching from Zoloft to Prozac, it’s important to talk to your healthcare provider.

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In Conclusion - What to Expect Switching from Zoloft to Prozac

Switching from Zoloft to Prozac usually isn’t difficult. Typically, your healthcare provider will tell you to gradually taper your dosage of Zoloft over the course of a few weeks, then start your usage of Prozac once Zoloft is out of your system.

In certain cases, you may need to taper on a shorter or longer schedule. Follow your healthcare provider’s instructions and keep them informed if you experience any side effects or changes in your symptoms during the process of switching medications.

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.

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