Aceclofenac is a non-steroidal anti-inflammatory drug (NSAID) analog of Diclofenac. It is used for the relief of pain and inflammation in rheumatoid arthritis, osteoarthritis and ankylosing spondylitis. The dose is 100 mg twice daily, and should not be given to people with porphyria or breastfeeding mothers and is not recommended for children. Aceclofenac is a cytokine inhibitor. Aceclofenac works by blocking the action of a substance in the body called cyclo-oxygenase. Cyclo-oxygenase is involved in the production of prostaglandins (chemicals in the body which cause pain, swelling and inflammation). Aceclofenac is the glycolic acid ester of diclofenac. The incidence of gastric ulcerogenicity of aceclofenac has been reported to be significantly lower than that of other frequently prescribed NSAIDs: for instance, 2-fold less than naproxen, 4-fold less than diclofenac, and 7-fold less than indomethacin. Aceclofenac is metabolized in human hepatocytes and human microsomes to form [2-(2',6'-dichloro-4'-hydroxy- phenylamino)phenyl] acetoxyacetic acid as the major metabolite, which is then further conjugated.