Does Tylenol PM show up on a drug test? 

Does Tylenol PM show up on a drug test? 

Tylenol PM can show up on a drug test. Tylenol PM has two active ingredients – Acetaminophen and Diphenhydramine. If we talk about Acetaminophen, it does not show up on a drug test. 

The medication is a simple, non-opioid painkiller which does not cause a false positive for any controlled substance. Diphenhydramine, on the other hand, is the main reason why Tylenol PM can show up on a drug test. 

Diphenhydramine is an antihistamine which can show a false positive for Opioids – like Methadone (1). 

Now, Diphenhydramine is not structurally similar to Opioids, but the standard drug immunoassays contain antibodies which can cross-react with the medication and show a false positive. 

These preliminary testing procedures are not considered accurate and they are prone to causing false positives. 

How long does Tylenol PM stay in your system? 

Tylenol PM has a half-life of about 10 hours, in which Acetaminophen starts to break down earlier than Diphenhydramine. The entire elimination process of this medication can take up to 2 days. 

However, this time duration can vary from person to person as it can depend on different factors, like your age, weight, dose, frequency, any pre-existing health condition, and overall physiological well-being. 

How to avoid Tylenol PM showing up on a drug test? 

You can avoid Tylenol PM causing a false positive by not taking the medication during the last 48 hours before your test. 

However, you don’t need to stop the medications you’re currently taking for the test and you can simply inform the testing authority about the medications you’re taking. 

It is a well-known fact that a number of medications can cause a false positive on drug urine immunoassays. If you’re going for more accurate testing procedures like Gas Chromatography – Mass spectroscopy (GC-MS), then you don’t need to worry about false positives. 

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Alyson Schwebach, Jennifer Ball. Urine Drug Screening: Minimizing False Positives and False Negatives to Optimize Patient Care. US Pharm. 2013;38(12):1-6. Available at: