Thiocolchicoside and Diclofenac| which relieves muscle pain. Thiocolchicoside is a muscle relaxant. It works on the centers in the brain and spinal cord to relieve muscle stiffness or spasm and improve movement of muscles. Diclofenac is a non-steroidal anti-inflammatory drug (NSAID) which works by blocking the release of certain chemical messengers in the brain that cause pain and inflammation (redness and swelling).