Suxibuzone is a prohibited substance under international equine competition rules. Treatment with Danilon Equidos should be stopped for a suitable time prior to competing. Follow RCVS guidance on elimination times for various anti-inflammatory drugs. Suxibuzone is a NSAID with anti-inflammatory, antipyretic and analgesic properties and low ulcerogenic potential. Its mechanism of action is based on the inhibition of cyclo-oxygenase. The therapeutic effects are mainly due to the inhibition of the biosynthesis of prostaglandins, which act as peripheral mediators of pain and trigger the synthesis of endogenous pyrogens and mediators in the inflammatory process. It also inhibits platelet aggregation. After oral administration, suxibuzone is readily absorbed and it is metabolized by the hepatic microsomal system producing phenylbutazone, oxyphenbutazone and γ - hydroxyphenylbutazone. As happens with other NSAIDs, the duration of the clinical response is much longer than the plasma half-life. Significant concentrations of both active metabolites are found in synovial fluid for at least 24 hours after administration.