Naproxen 500 mg is a prescription-strength anti-inflammatory medication used to treat pain and swelling from conditions like rheumatoid arthritis, osteoarthritis, ankylosing spondylitis, gout flares, tendinitis, bursitis, and menstrual cramps. It belongs to a class of drugs called NSAIDs (nonsteroidal anti-inflammatory drugs), and the 500 mg tablet is the highest single-dose strength available, typically taken twice daily.
Conditions Treated With Naproxen 500 mg
The 500 mg strength is primarily prescribed for chronic inflammatory conditions that need consistent, higher-dose relief. Rheumatoid arthritis and osteoarthritis are the most common reasons people take it long term. For these conditions, the standard starting dose is 250 mg, 375 mg, or 500 mg twice a day, morning and evening, with a maximum of 1,500 mg per day.
Naproxen 500 mg is also used for ankylosing spondylitis (inflammatory arthritis of the spine), acute gout attacks, tendinitis, bursitis, and moderate to severe menstrual pain. For short-term problems like a gout flare or a sports injury, you may only need it for a few days to a couple of weeks. For arthritis, many people take it daily for months or longer.
How It Differs From Over-the-Counter Naproxen
You can buy naproxen over the counter (sold as Aleve), but those tablets contain 220 mg of naproxen sodium. Prescription naproxen 500 mg delivers more than double the active ingredient per tablet. The OTC version is designed for occasional headaches, minor aches, and fever. The 500 mg prescription strength is meant for more significant pain and inflammation that the lower dose can’t adequately control.
How Naproxen Works
When tissue is injured or inflamed, your body releases chemicals called prostaglandins that trigger pain, swelling, and redness. Naproxen blocks the enzymes (COX-1 and COX-2) responsible for producing these prostaglandins. With fewer prostaglandins circulating, inflammation decreases and pain eases. This is the same basic mechanism as ibuprofen, but naproxen lasts considerably longer in your system.
How Quickly It Works and How Long It Lasts
Pain relief typically begins within about 30 minutes of taking a dose. Naproxen has a long half-life of roughly 15 hours, which means a single dose keeps working far longer than ibuprofen (which lasts about 4 to 6 hours). This is why naproxen is dosed just twice a day rather than every few hours. For many people, this makes it more convenient for managing chronic pain that persists throughout the day.
Common Side Effects
The most frequent side effects are digestive: nausea, gas, constipation, and heartburn. Some people also experience headache, dizziness, drowsiness, or ringing in the ears. These tend to be mild and often improve as your body adjusts to the medication.
More concerning is the potential for stomach ulcers and bleeding. NSAIDs like naproxen can cause ulcers, bleeding, or even holes in the stomach or intestinal lining, sometimes without warning symptoms. Signs to watch for include stomach pain, vomit that looks bloody or like coffee grounds, and black or tarry stools. Older adults and anyone with a history of stomach ulcers face higher risk.
Cardiovascular and Kidney Risks
Naproxen carries an FDA boxed warning (the most serious category) for cardiovascular risk. All NSAIDs increase the chance of heart attack and stroke, and this risk can appear early in treatment and grows with longer use. Naproxen should not be taken after coronary artery bypass surgery.
Your kidneys can also be affected. Naproxen reduces blood flow to the kidneys, which is usually harmless in healthy people but can worsen kidney function if you’re dehydrated, have heart failure, or already have kidney problems. Signs of kidney trouble include decreased urination, painful urination, or cloudy urine. If you take naproxen long term, periodic blood pressure checks and blood work to monitor kidney and liver function are standard practice.
Drug Interactions to Know About
Naproxen interacts with several commonly prescribed medications. If you take blood pressure drugs like ACE inhibitors, ARBs, or beta-blockers, naproxen can blunt their effectiveness and raise your blood pressure. Diuretics (water pills) can also become less effective.
Taking naproxen alongside blood thinners or antiplatelet medications increases your bleeding risk significantly. The combination with antidepressants in the SSRI class (commonly prescribed for depression and anxiety) also raises the chance of upper gastrointestinal bleeding, because SSRIs independently affect how platelets function and increase stomach acid. If you take lithium, naproxen can push lithium levels higher in your blood, potentially causing toxicity.
Long-Term Use Considerations
For people with chronic arthritis, naproxen 500 mg is often taken daily for extended periods. This is generally manageable but requires ongoing monitoring. Your prescriber will likely check blood counts periodically, since naproxen can contribute to anemia through gradual blood loss in the digestive tract or by affecting how your body produces blood cells. Patients starting with low hemoglobin levels need especially close tracking.
If you notice any changes in vision while taking naproxen long term, that warrants attention. Animal studies with this drug class have shown eye-related effects, and the FDA recommends an eye exam if visual disturbances develop. Blood pressure monitoring throughout treatment is also recommended, since even people without a history of hypertension can see their numbers creep up on long-term NSAID therapy.