The shelf life for Naproxen tablets is three years from the manufacturing date. Ideal storage conditions include a dry, dark place at temperatures below 77 degrees Fahrenheit. Naproxen tablets generally come in polypropylene containers, according to electronic Medicines Compendium, or eMC.
The expiration date for Naproxen represents the end of the period of time in which the manufacturer guarantees full potency. Tablets and capsules often last well past the printed expiration date, and no research connects the use of expired Naproxen to toxic effects. The primary risk of taking expired Naproxen is a failure to receive the full anti-inflammatory benefits, states Drugs.com.