Can Hydroxyzine cause a false positive for a Benzodiazepine?

Can Hydroxyzine cause a false positive for a Benzodiazepine?

No, Hydroxyzine is not associated with causing a false positive for Benzodiazepine. The primary method of drug testing is urine analysis.

Hydroxyzine usually remains detectable in your urine for a few more days, typically 4-5, since you last took it. Although Hydroxyzine is not likely to cause a Benzodiazepine false positive, it can cause a false positive for Tricyclic antidepressants (TCAs). 

It is a class of antidepressants which was once used as the first line of treatment for depression but was replaced by the newer antidepressants because of their severe side effect profile. A number of other allergy medications are associated with causing a false positive for TCAs and other drugs. 

What should be done if you get a false positive for Benzodiazepine? 

If you received your test results and you’re false positive for Benzodiazepine, Hydroxyzine is not the one responsible for causing such a result. 

If that’s the case and you have not been abusing Benzos, it’s best to go for detailed and more sensitive analyzing techniques to determine the exact chemical that could be causing this. 

Urine analysis is not 100% accurate because the antibodies it uses to bind with a certain drug metabolite can bind mistakenly with something else and show a false positive. Detailed procedures like Gas Chromatography/Mass Spectrometry (GC/MS) should be considered. (1) 

How to prevent getting a false positive?

You may not be able to completely prevent getting a false positive if going for a urine drug immunoassay. However, you can inform the drug testing authorities about the medications you are currently taking prior to the test. 

Urine drug immunoassays are known for showing inaccurate results at times and a lot of medications, including OTC meds, are known for causing false positives. So, getting a false positive because of a prescription or OTC medication will not affect you if the authority already knows that you are taking them. 

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References

1.-

Ramoo B, Funke M, Frazee C, Garg U. Comprehensive Urine Drug Screen by Gas Chromatography/Mass Spectrometry (GC/MS). Methods Mol Biol. 2016;1383:125-31. doi: 10.1007/978-1-4939-3252-8_15. PMID: 26660182. Available from: https://pubmed.ncbi.nlm.nih.gov/26660182/