phenazone + phenylbutazone

Phenazone + phenylbutazone is a theoretical or rarely used fixed-dose combination of two nonsteroidal anti-inflammatory drugs (NSAIDs): phenazone (antipyrine) and phenylbutazone. Both drugs function as small-molecule cyclooxygenase (COX) inhibitors, providing anti-inflammatory, analgesic, and antipyretic effects. Phenylbutazone is primarily used in veterinary medicine for treatment of pain and inflammation, especially in horses, and works by inhibiting prostaglandin synthesis via cyclooxygenase blockade[2][4][5]. Phenazone also inhibits prostaglandin synthesis, but its current clinical use is limited, and its inclusion in combination therapies is not well established. Combining multiple NSAIDs increases the risk of adverse effects, notably gastrointestinal ulceration, renal damage, protein loss, and hematologic toxicity. The combination of phenylbutazone with another NSAID (such as flunixin) has been shown to carry high risk for gastrointestinal complications and is generally cautioned against in clinical practice[1].