Detailed Naproxen dosage information for adults and children. Includes dosages for Pain, Osteoarthritis, Rheumatoid Arthritis and more; plus renal, liver and dialysis adjustments. Naproxen is a nonsteroidal anti-inflammatory drug (NSAID). It works by reducing hormones that cause inflammation and pain in the body. Naproxen is used to treat pain or inflammation caused by conditions such as arthritis, ankylosing spondylitis, tendinitis, bursitis, gout, or menstrual cramps. Nonprescription naproxen is used to reduce fever and to relieve mild pain from headaches, muscle aches, arthritis, menstrual periods, the common cold, toothaches, and backaches. Naproxen is a nonsteroidal anti-inflammatory drug (NSAID) used to relieve symptoms of arthritis (eg, osteoarthritis, rheumatoid arthritis, or juvenile arthritis) such as inflammation, swelling, stiffness, and joint pain. Overview: Naproxen is a nonsteroidal anti-inflammatory drug (NSAID) used to relieve pain, reduce swelling, and lower fever. Common side effects include belly pain, upset stomach, heartburn, or. NHS information about naproxen, including what it's used for, who can take it, how to take it and side effects. Naproxen and naproxen sodium are prototypical anti-inflammatory agents (NSAIAs) that also exhibit analgesic and antipyretic activity. Naproxen is used as a treatment to relieve pain from various conditions such as headaches, muscle aches, tendonitis, dental pain, and menstrual cramps. It also reduces pain, swelling, and joint stiffness caused by conditions such as arthritis, bursitis, and gout attacks. Naproxen sodium is available as both an immediate-release and an extended-release tablet. The extended-release formulations (sometimes called sustained release , or enteric coated ) take longer to take effect than the immediate-release formulations and therefore are less useful when immediate pain relief is desired. This article provides an overview of naproxen, including how it works, its uses, the potential side effects, and more.