Celecoxib. Molecular model of the drug celecoxib (C17.H14.F3.N3.O2.S). This is a COX-2 selective nonsteroidal anti-inflammatory drug (NSAID), sold under the brand name Celebrex. It is used for osteoarthritis, rheumatoid arthritis, acute pain, musculoskeletal pain, painful menstruation, and ankylosing spondylitis. Atoms are represented as spheres and are colour-coded: carbon (grey), hydrogen (white), nitrogen (dark blue), oxygen (red), sulfur (yellow) and fluorine (light blue).