Naproxen is a pain reliever and anti-inflammatory drug that works by blocking your body’s production of prostaglandins, the chemicals responsible for pain, swelling, and fever. It belongs to the class of drugs known as NSAIDs (nonsteroidal anti-inflammatory drugs) and is available both over the counter and by prescription. What sets naproxen apart from similar drugs like ibuprofen is its long duration of action, which means fewer doses throughout the day.
How Naproxen Works in Your Body
Your body produces enzymes called COX-1 and COX-2. These enzymes convert a fatty acid in your cells into prostaglandins, which trigger inflammation, amplify pain signals, and raise your body temperature during illness or injury. Naproxen blocks both of these enzymes, cutting off prostaglandin production at the source.
This creates two distinct effects. The anti-inflammatory effect comes from shutting down COX-2, which drives swelling and inflammation at injury sites. The pain-relieving effect is partly direct (less inflammation means less pain) and partly indirect: prostaglandins E and F specifically sensitize your pain receptors, making them fire more easily. By reducing these prostaglandins, naproxen essentially turns down the volume on your pain signaling system. It also lowers fever by the same mechanism, since prostaglandins in the brain are what push your body temperature up during infection.
Naproxen is slightly more active against COX-1 than COX-2, which matters for understanding both its benefits and its side effects.
What Naproxen Is Used For
Naproxen is FDA-approved to treat a broad range of pain and inflammatory conditions:
- Arthritis: rheumatoid arthritis, osteoarthritis, and ankylosing spondylitis (a type of inflammatory spinal arthritis)
- Soft tissue inflammation: tendinitis and bursitis
- Acute gout flares
- Menstrual cramps (primary dysmenorrhea)
- Mild to moderate pain: headaches, dental pain, muscle aches, back pain
For chronic conditions like arthritis, naproxen is typically taken daily on an ongoing basis. For acute problems like gout flares or menstrual cramps, it’s used for shorter periods until symptoms resolve.
How Quickly It Works and How Long It Lasts
Naproxen sodium (the form sold over the counter as Aleve) reaches peak levels in your blood within one to two hours when taken on an empty stomach. If you take it with food, that peak shifts to around two to three hours, though food can delay it further in some people.
The key advantage of naproxen over ibuprofen is duration. Naproxen’s long half-life means a single dose provides relief for 8 to 12 hours, so most people only need to take it twice a day. Ibuprofen, by comparison, typically requires dosing every four to six hours. For people managing ongoing pain, this means fewer pills and more consistent relief throughout the day and overnight.
OTC vs. Prescription Strength
Over-the-counter naproxen sodium (Aleve) comes in 220 mg tablets. The typical OTC dose is one tablet every 8 to 12 hours. Prescription naproxen comes in higher strengths, and doses vary significantly depending on the condition being treated. For arthritis, prescription doses commonly range from 250 to 500 mg taken twice daily, with a maximum of 1,500 mg per day. For an acute gout attack, the initial dose is higher (750 mg), then drops to 250 mg every eight hours until the flare subsides.
It’s worth noting that naproxen and naproxen sodium are slightly different formulations. Naproxen sodium dissolves and absorbs a bit faster. The milligram numbers aren’t directly interchangeable: 220 mg of naproxen sodium delivers roughly 200 mg of naproxen itself.
Stomach and Digestive Side Effects
The most common downside of naproxen is its effect on your stomach and digestive tract. This isn’t random bad luck. It’s a direct consequence of how the drug works. The same COX-1 enzyme that naproxen blocks also produces prostaglandins that maintain the protective mucus lining of your stomach. When that lining thins, your stomach becomes vulnerable to its own acid.
Minor digestive symptoms like nausea, stomach pain, heartburn, and diarrhea affect 10% to 60% of people who take NSAIDs regularly. Among chronic users, endoscopic studies show that 20 to 30% develop ulcers, though many of these cause no symptoms. The more serious concern is that roughly 2% of average-risk NSAID users per year experience complications like significant bleeding or perforation. In high-risk patients (older adults, those with a history of ulcers, or people taking blood thinners), that rate climbs to as high as 10% per year. These complications can develop without warning symptoms.
Taking naproxen with food or using a stomach-protecting medication can reduce but not eliminate this risk. The risk increases with higher doses and longer use.
Cardiovascular Safety Compared to Other NSAIDs
One area where naproxen consistently stands out is heart safety. A large study published by the American Heart Association found that among patients who had been hospitalized for serious coronary heart disease, naproxen users had the lowest rates of heart attack, stroke, and cardiovascular death compared to users of other NSAIDs. Naproxen users at doses of 1,000 mg or more per day showed no increased cardiovascular risk compared to people not taking any NSAID at all.
By contrast, diclofenac users had a 44% higher risk of serious coronary events compared to naproxen users, and ibuprofen users had a 25% higher risk of serious cardiovascular events or death. Higher doses of celecoxib (a COX-2 selective NSAID) carried a 61% increased risk of serious coronary heart disease compared to naproxen. This cardiovascular advantage is one reason doctors often prefer naproxen for patients who need long-term NSAID therapy, particularly those with heart disease risk factors.
Who Should Avoid Naproxen
Naproxen is not safe for everyone. It is contraindicated for people who have had allergic reactions to aspirin or other NSAIDs, including asthma attacks, hives, or swelling triggered by these drugs. Severe, sometimes fatal anaphylactic reactions have been reported in people with this history. It also cannot be used in the period around coronary artery bypass graft (CABG) surgery due to elevated cardiovascular risk in that setting.
People with kidney disease need to be cautious, since prostaglandins help regulate blood flow to the kidneys. Blocking their production can worsen kidney function. Similarly, naproxen can raise blood pressure and cause fluid retention, which matters for people with heart failure or hypertension. If you take blood thinners, naproxen increases bleeding risk both by impairing the blood’s ability to clot (through COX-1 inhibition) and by potentially causing GI bleeding that is harder to stop.
Long-term use at higher doses carries the greatest risk profile. For occasional use at OTC doses in otherwise healthy adults, naproxen remains one of the better-tolerated NSAID options available.