Naproxen is a methoxynaphthalene that is 2-methoxynaphthalene substituted by a carboxy ethyl group at position 6. Naproxen is a non-steroidal anti-inflammatory drug commonly used for the reduction of pain, fever, inflammation and stiffness caused by conditions such as osteoarthritis, kidney stones, rheumatoid arthritis, psoriatic arthritis, gout, ankylosing spondylitis, menstrual cramps, tendinitis, bursitis, and for the treatment of primary dysmenorrhea. It works by inhibiting both the COX-1 and COX-2 enzymes. It has a role as a non-steroidal anti-inflammatory drug, a non-narcotic analgesic, an antipyretic, a xenobiotic, a gout suppressant, a cyclooxygenase 2 inhibitor, a cyclooxygenase 1 inhibitor, an environmental contaminant and a drug allergen. It is a monocarboxylic acid and a methoxynaphthalene. It is a conjugate acid of a naproxen(1-).