Can Naproxen show up on a drug test? 

Naproxen can show up on a drug test, as the medication is known for causing false positives for Cannabinoids and Barbiturates (1). Naproxen is a non-steroidal anti-inflammatory drug (NSAID) and is one of the commonly used over-the-counter painkillers and anti-inflammatory medications. 

Although Naproxen is not structurally similar to any of the controlled illegal drug substances and is not known for causing addiction, it can still make you fail a drug test. However, the probability of failing a drug test on Naproxen also depends on the type of test you’re going for. 

Urine immunoassays are known to cause false positives because of the accuracy issues – as compared to more expensive and accurate drug testing procedures (2). 

How long does Naproxen stay in your system? 

Naproxen has a half-life of about 12-17 hours, which is the time taken by the drug to reduce its peak concentration to half. The remaining concentration of the drug further reduces to half within the next 12-17 hours. 

This process continues until the drug is completely eliminated from your body and it can take up to 3-4 days in total. 

However, some people may get rid of Naproxen over an extended period of time as a lot of different factors can slow down drug metabolism in your body, like your age, weight, dose, frequency, any pre-existing health condition, and overall physiological well-being. 

How to avoid a false positive caused by Naproxen? 

You can avoid a false positive on Naproxen if you take your last dose 3-4 days before your drug testing date. This way your body will have enough time to get rid of the drug completely. 

The lesser concentration of the drug has a lesser chance of causing a false positive for any controlled substance or drug of abuse. You can also go for more accurate testing procedures, like Gas chromatography-mass – Mass spectroscopy (GC-MS). (3) 

This testing is often performed to confirm the findings of preliminary drug testing procedures and it can identify the exact chemical present in your body. However, these tests are kinda expensive and not everyone can afford them. 

References

  1. US Pharmacist. Urine Drug Screening: Minimizing False-Positives and False-Negatives to Optimize Patient Care, 2016;41(8):26-30. Available from: https://www.uspharmacist.com/article/urine-drug-screening-minimizing-false-positives-and-false-negatives-to-optimize-patient-care
  2. Brahm NC, Yeager LL, Fox MD, Farmer KC, Palmer TA. Commonly prescribed medications and potential false-positive urine drug screens. Am J Health Syst Pharm. 2010 Aug 15;67(16):1344-50. doi: 10.2146/ajhp090477. PMID: 20689123. Available from: https://pubmed.ncbi.nlm.nih.gov/20689123/
  3. 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/

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References

1.-

US Pharmacist. Urine Drug Screening: Minimizing False-Positives and False-Negatives to Optimize Patient Care, 2016;41(8):26-30. Available from: https://www.uspharmacist.com/article/urine-drug-screening-minimizing-false-positives-and-false-negatives-to-optimize-patient-care

2.-

Brahm NC, Yeager LL, Fox MD, Farmer KC, Palmer TA. Commonly prescribed medications and potential false-positive urine drug screens. Am J Health Syst Pharm. 2010 Aug 15;67(16):1344-50. doi: 10.2146/ajhp090477. PMID: 20689123. Available from: https://pubmed.ncbi.nlm.nih.gov/20689123/

3.-

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/