Phenylbutazone is a non-steroidal anti-inflammatory drug (NSAID) related to the pyrazolone derivative. The anti-inflammatory and analgesic effects of phenylbutazone depend on its ability to inhibit hypothalamic cyclo-oxygenase
leading to reduced synthesis of prostaglandins and related compounds. This is followed by activation of heat loss mechanisms, i.e. panting, sweating and peripheral vasodilatation, and inhibition of thermogenesis. It also has the ability to trap or scavenge toxic oxygen-free radicals.
Cabutazone is a nonsteroidal anti-inflammatory, analgesic and antipyretic.