Phenylbutazone is a pyrazolone non-steroidal anti-inflammatory, analgesic and antipyretic agent.
ATCvet code: QM01AA01
Pharmacodynamic properties
Phenylbutazone is a pyrazolone non-steroidal anti-inflammatory, analgesic and antipyretic agent. Phenylbutazone acts by inhibiting the production of prostaglandins. Prostaglandins possess a wide variety of physiological properties, including those involved in the production of pain, inflammation and pyrexia. The main metabolite, oxyphenbutazone, possesses similar pharmacological properties.
Pharmacokinetic properties
The serum half-life is dose-dependent and ranges from 3.5-6 hours. Therapeutic efficacy may, however, last more than 24 hours, probably due to irreversible binding of phenylbutazone to cyclooxygenase. Phenylbutazone is nearly completely metabolised, primarily to oxyphenbutazone (pharmacologically active) and hydroxyphenbutazone. Oxyphenbutazone has been detected in the urine for up to 48 hours after a single administration. Phenylbutazone is more rapidly excreted into alkaline than acidic urine.