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When someone is suffering from a mental illness or eating disorder, it’s only normal to want an improvement in their condition as soon as possible. For those just starting their fluoxetine hydrochloride (Prozac) treatments, they may rightfully ask, “How long does it take for Prozac to work?”

How Long Does It Take For Prozac To Work?

Prozac (fluoxetine hydrochloride) is a selective serotonin reuptake inhibitor, or SSRI. This class of antidepressants works by preventing the reuptake, or reabsorption, of the “feel-good chemical” serotonin. The result of this inhibition is increased levels of serotonin, which experts link to improved mood.

Fluoxetine has a long half-life, which is the period of time it takes for the body to eliminate half of this substance; it takes several half-lives to completely clear a substance from the body. Given this long half-life, it takes a little longer for fluoxetine to begin working. While patients may notice an improvement in their symptoms within the first week or two of starting Prozac, they likely won’t feel the drug’s full effects for another four weeks.

Final Thoughts

To feel the full effects of Prozac, patients need to wait roughly 4 to 6 weeks; this adjustment phase may be marked by unpleasant symptoms. That said, some patients have reported noticing improvements within a week or two of starting this drug.

Disclaimer: this article does not constitute or replace medical advice. If you have an emergency or a serious medical question, please contact a medical professional or call 911 immediately. To see our full medical disclaimer, visit our Terms of Use page.

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