Meclofenamic acid (brand Meclomen) is a drug used for joint, muscular pain, arthritis and dysmenorrhea. It is a member of the NSAID class of drugs and was approved by the FDA in 1980. It inhibits the synthesis of prostaglandins.
Meclofenamic acid is sold under the trade name "Arquel" for use in horses, and is administered as an oral granual form at a dose of 2.2 mg/kg/day. It has a relatively slow onset of action, taking 36-48 hours for full effect, and is most useful for treatment of chronic musculoskeletal disease. It has been found to be beneficial for the treatment of navicular syndrome, laminitis, and osteoarthritis, in some cases having a more profound effect than the commonly-used NSAID phenylbutazone. However, due to cost, it is not routinely used in practice. Toxicity due to excessive dosage is similar to that of phenylbutazone, including depression, anorexia, weight loss, edema, diarrhea, oral ulceration, and decreased hematocrit.