Naproxen

Naproxen, often sold as Aleve, belongs to a class of drugs called nonsteroidal anti-inflammatory drugs (NSAIDs). People take it by mouth to manage pain, menstrual cramps, fever, and inflammatory conditions like rheumatoid arthritis and gout. It comes in both immediate-release and delayed-release forms, and there is also a version called naproxen sodium that dissolves more easily in the body. The drug starts working within an hour, and its effects can last up to twelve hours. It is listed by the World Health Organization as an essential medicine.

Common side effects include dizziness, headache, heartburn, stomach pain, bruising, and allergic reactions. More serious risks involve heart disease, stroke, gastrointestinal bleeding, and stomach ulcers, though the heart risk may be lower than with some other NSAIDs. People with kidney problems should avoid it, and it is not recommended during the third trimester of pregnancy. Naproxen works by blocking an enzyme called COX, which reduces the production of prostaglandins—chemicals that cause inflammation. The liver breaks it down into inactive substances.

Naproxen was first patented in 1967 and approved for medical use in the United States in 1976. It is sold over-the-counter and as a generic drug. In 2023, it was the 103rd most prescribed medication in the U.S., with over 6 million prescriptions. Doctors use it for many inflammatory conditions, including migraines, osteoarthritis, kidney stones, tendinitis, and post-operative pain. Naproxen sodium is also used as a "bridge therapy" to help people gradually stop other headache medications.

The extended-release form takes longer to work, making it better for chronic conditions rather than immediate pain relief. During pregnancy, naproxen should be avoided because prostaglandins are important for fetal blood vessel and kidney function, especially in the third trimester. Small amounts pass into breast milk, but side effects in nursing infants are rare. Heavy use raises the risk of kidney failure and end-stage renal disease. About 3% of users may experience leg muscle cramps. In 2020, the U.S. FDA required warnings about low amniotic fluid in babies when NSAIDs are taken after 20 weeks of pregnancy.

Gastrointestinal issues like heartburn, constipation, diarrhea, ulcers, and stomach bleeding can occur. Taking it with or after food reduces these risks. People with a history of ulcers or inflammatory bowel disease should consult a doctor first. In the U.S., naproxen carries a boxed warning about gastrointestinal bleeding. Compared to ibuprofen (low risk) and indometacin (high risk), naproxen poses an intermediate risk of stomach ulcers. To lower this risk, it is sometimes combined with a proton-pump inhibitor during long-term use.

Cardiovascular risks, including heart attacks and strokes, are linked to both selective and nonselective NSAIDs, but naproxen has the smallest overall cardiovascular risk. One study found that high-dose naproxen nearly completely suppressed platelet thromboxane throughout the dosing period and did not appear to increase cardiovascular disease risk, unlike other NSAIDs. However, naproxen is associated with higher rates of upper gastrointestinal bleeding compared to other NSAIDs. It may also interact with antidepressants, lithium, methotrexate, probenecid, warfarin, and blood pressure medications.