OverviewDosageSide EffectsInteractionsHalf-Life

Naproxen is currently the 71st most commonly prescribed drug in the United States. In 2017 alone, there were over 11 million prescriptions. Considering how popular this drug is right now, it pays to know a little bit more about this medication, including how long naproxen stays in your system.

How long does naproxen stay in your system?

NSAIDs like naproxen may result in false-positive results for both THC and barbiturate tests. Therefore, it pays to know how long this drug will stay in your system. Since it takes about 5 half-lives for the body to clear a substance, traces of naproxen may remain in your system up to roughly 85 hours after last use.

Naproxen Half-Life

The FDA states the following information regarding naproxen half-life:

Mean effective half-life: 12 to 17 hours

Time to steady-state: 4 to 5 days 

Predicted accumulation ratio (in synovial fluid): 2.4

Terminal phase half-life: 10 to 20 hours

The body absorbs naproxen wholly and rapidly; it then binds with plasma albumin (a type of protein). Following the biotransformation of the drug to glycoconjugates and sulfate metabolites, it excretes naproxen in the urine. 

Does naproxen really last 12 hours?

The long-lasting nature of this drug is one characteristic that makes it stand out when compared to other NSAIDs like aspirin or ibuprofen. 

Why can’t you lay down for 10 minutes after taking naproxen?

Naproxen can irritate the stomach and lead to heartburn. It is therefore better to sit up to prevent injury to the esophagus (throat) from stomach acid.  It may be taken with food or milk to help with gastrointestinal side effects.

Disclaimer: this article does not constitute or replace medical advice. If you have an emergency or a serious medical question, please contact a medical professional or call 911 immediately. To see our full medical disclaimer, visit our Terms of Use page.

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