How Long It Takes for Naproxen to Work, Plus 4 More Naproxen FAQs

Naproxen (Aleve, Naprosyn) is a popular pain relief medication. You’ve likely seen it available over the counter (OTC) at your local pharmacy. But it’s also available with a prescription, at a higher dose.

Naproxen is an nonsteroidal anti-inflammatory drug (NSAID). The OTC version is labeled to treat fever and mild to moderate pain. Prescription-strength naproxen is FDA-approved to treat osteoarthritis and rheumatoid arthritis, among other painful conditions.

If your healthcare provider has recommended taking naproxen, they likely provided you with information about the medication. But it’s normal to think of more questions after your visit or phone call with your provider. If that’s the case for you, you’ve come to the right place. Below, we’ll answer five common questions about naproxen.

1. How long does it take for naproxen to work?

It usually takes about 30 to 60 minutes for naproxen to start working for mild to moderate pain. It may take up to 4 hours to feel the full effects, though. If your symptoms aren’t improving within a few hours after taking naproxen, don’t take an extra dose. Taking too much naproxen can be dangerous. Follow the instructions from your healthcare provider or those found on the OTC label.

For arthritis or inflammatory conditions, it may take about a week for naproxen to start relieving symptoms. But it could take 2 weeks or longer to experience its full anti-inflammatory benefits. If you think naproxen isn’t working how it should, check with your healthcare provider. They can determine if you need a dose change or a different medication.

2. How long does naproxen stay in your system?

Naproxen may stay in your system for up to 85 hours (about 3.5 days) after taking a dose. But even though it’s present in your body for several days, you likely won’t feel the effects for that long.

When taken occasionally, naproxen starts wearing off about 12 hours after taking a dose. That’s why it’s typically recommended to take doses of naproxen every 8 to 12 hours.

With daily use, it’s a little different. You likely won’t notice an increase in inflammation for about 4 to 5 days after stopping naproxen. However, pain relief may wear off sooner.

3. Should you take naproxen with food?

According to its labeling, naproxen can be taken with or without food. Either way, it’s a good idea to take your dose with a full glass of water. If taking the medication gives you an upset stomach, taking it with food or a glass of milk may help.

However, organizations across the globe recommend taking NSAIDs like naproxen with food or milk to help reduce stomach irritation. Just keep in mind that taking it with food can also cause it to take longer to work.

Let your healthcare provider know if you’re experiencing excessive or persistent stomach pain. In severe cases, NSAIDs like naproxen can cause stomach ulcers or bleeding.

4. How does naproxen work?

Like other NSAIDs, naproxen works by blocking the production of prostaglandins in the body. Prostaglandins are natural substances the body produces that help create pain or swelling when the body is hurt or sick. They’re also responsible for causing fevers, widening or narrowing blood vessels, and affecting blood clotting, among other effects.

Specifically, naproxen blocks cyclooxygenase (COX) proteins. These proteins produce prostaglandins. Blocking COX proteins helps reduce the amount of prostaglandins. And lower levels of prostaglandins means less fever, pain, and inflammation.

5. Does naproxen cause weight gain?

Naproxen doesn’t usually cause weight gain, but weight changes are listed in its package insert as a rare side effect. If you notice weight gain with naproxen, it’s likely due to water retention. For most people, this appears as swollen ankles or legs. This type of weight gain should be minor and resolve once you stop taking naproxen.

But if you have heart failure, naproxen could worsen the condition. Fluid buildup if you have heart failure can cause symptoms like ankle swelling, shortness of breath, and unexplained or rapid weight gain. Your healthcare provider may ask you to avoid taking naproxen and other NSAIDs if you have heart failure. Be sure to let your healthcare provider know if you have unusual or excessive weight changes while taking naproxen.

How to save on naproxen

There are many ways to save on naproxen, which is available as both a brand-name and generic medication. By having your healthcare provider write a prescription for OTC naproxen, GoodRx can help you save over 50% off the average retail price.

OTC naproxen's price at certain pharmacies is as low as $5.82 with a free GoodRx discount. Prescription-strength naproxen's price at certain pharmacies is as low as $2.80 with a free GoodRx discount.

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Written by:

Austin Ulrich, PharmD, BCACP

Austin Ulrich, PharmD, BCACP, is a board-certified ambulatory care clinical pharmacist. In his early career, he provided direct patient care in a variety of settings, including hospital and community pharmacies, and in a primary care clinic as a clinical pharmacist.

Edited by:

Christina Aungst, PharmD

Christina Aungst, PharmD, is a pharmacy editor for GoodRx. She began writing for GoodRx Health in 2019, transitioning from freelance writer to editor in 2021.

Reviewed by:

Stacia Woodcock, PharmD

Stacia Woodcock, PharmD, is a pharmacy editor for GoodRx. She earned her Doctor of Pharmacy degree from the University of Kentucky and is licensed in New York and Massachusetts.

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