Can Benadryl cause a false positive for TCA? A look into medications and pharmacology
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4 min read
It is a fact that certain over-the-counter medications, including Benadryl (diphenhydramine), can lead to a false positive result for Tricyclic Antidepressants (TCAs) on standard drug screening tests. This phenomenon is a well-documented issue in pharmacology and toxicology that can cause significant confusion for both patients and clinicians. The reason lies in the biochemical limitations of initial immunoassay screens and the structural similarities between Benadryl and TCAs.
