Mefenamic acid is a nonsteroidal anti-inflammatory drug (NSAID) that is used to relieve mild to moderate pain, such as pain from arthritis, dysmenorrhea (painful menstruation), and other musculoskeletal conditions. It works by inhibiting the enzyme cyclooxygenase (COX), which is responsible for producing prostaglandins that cause inflammation, pain, and fever. Mefenamic acid is typically used for short-term pain relief and is considered effective for managing inflammation.