Does Prozac show up on a drug test? (+5 factors)

In this brief article, we will answer the question, “Does Prozac show up on a drug test?” and other questions, like Why can Prozac show up on a drug test?; What determines Prozac’s duration of detectability in a drug test?; How to prevent false detection of Prozac? and Is there any research on drug testing for Prozac? 

Does Prozac show up on a drug test?

Yes, Prozac does show up on a drug test. Usually, Prozac (Fluoxetine) and other anti-depressants do not show up in regular drug tests. Therefore, individuals must disclose their prescription medication use to the testing facility to ensure accurate interpretation of results. 

Why can Prozac show up on a drug test?

Prozac might show up on a drug test because, despite its low risk of abuse, it has the potential for a false positive result in drug testing. Due to its longer-acting nature, Prozac takes around 25 days or more to completely exit your system. (1)

After being absorbed by the gut, Prozac undergoes metabolism in the liver, and its metabolites circulate in the bloodstream. Even post-medication cessation, Prozac can persist in the blood. (1)

Similarly, a urine test can detect the medication in the urine for a duration similar to that in the blood. (1)

What determines Prozac’s duration of detectability in a drug test?

After you complete the tapering-off schedule of Prozac, as advised by your healthcare provider, it may still take some time for Prozac to fully exit your system. (1)

  • If you are older, you might find that your body takes a bit longer to metabolize Prozac. (1)


  • The duration for which Prozac stays in your system is often influenced by factors such as how long you have been taking it or if you are on other medications. (1)


  • Certain foods as demonstrated by the poppy seed bagel and poppy seed cake have been known to occassionally trigger false positive test results.


  • You can expect Prozac to linger in your system for a longer period if your metabolism is slower. (1)


  • Liver and kidney diseases can impact the presence of Prozac, in your blood altering the required dosage. As Prozac is eliminated through urine, problems with the liver or kidneys can extend its half-life. (1)

How to prevent a false detection of Prozac?

To avoid the false detection of Prozac in a drug test, you can make sure to take the following measures. 

  • Proactively inform the technician that you are taking Fluoxetine. Take your prescription bottle and ensure the drug is noted on your record. (2)


  • Due to the risk of a false positive, consider all drug screen tests presumptive until confirmed by a second testing technique like liquid or gas mass spectrometry. (2)


  • Discuss with your doctor the possibility of trying other anti-depressants like mirtazapine, if fluoxetine is causing false positives. (2)


  • Opt for a reliable drug testing kit to save time and ensure accurate results. (2)


  • Consume a sufficient amount of water to maintain energy levels and expedite the removal of drug metabolites. (2)

Is there any research on drug testing for Prozac?

Yes, a study was conducted to review potential false positive interferences with urine drug screen (UDS) immunoassays. The study analyzed 173 articles, narrowing down to 62, shedding light on analytes causing false positive results. (3)

The review identified false positives across various drug classes including amphetamines, opiates, benzodiazepines, cannabinoids and others. Notably, the study found that fluoxetine, the active ingredient in Prozac, can cause a false positive for amphetamines. (3)

The findings underscore the prevailing practice of treating positive immunoassay results as presumptive until validated by a second independent chemical technique. (3)


In this brief article, we have answered the question “Does Prozac show up on a drug test?” and other questions, like why can Prozac show up on a drug test, what determines Prozac’s duration of detectability in a drug test, how to prevent false detection of Prozac and is there any research on a drug testing for Prozac.

In my perspective, it’s crucial to recognize the possibility of Prozac showing up on a drug test. Therefore, I would recommend taking precautions to prevent false positive results. 


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Wooldridge, A. (2022, July 29). How long does Prozac stay in your system? Half-Life & More. K Health. 



Schimelpfening, N. (2023, April 19). Can antidepressants like Prozac show up on a drug test?. Verywell Mind.



Saitman, A., Park, H.-D., & Fitzgerald, R. L. (2014, September 38). False-positive interferences of common urine drug screen immunoassays: A Review. Journal of analytical toxicology.


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