Products
Phenylbutazone is now on the market in many countries only as a veterinary drug. Human drugs such as butazolidine are no longer available.
Structure and properties
Phenylbutazone (C19H20N2O2, Mr = 308.4 g/mol) exists as a white crystalline powder that is practically insoluble in water. The sodium salt is more soluble. Phenylbutazone is odorless and has a faintly bitter taste. Structurally, the substance belongs to the pyrazolones.
Effects
Phenylbutazone (ATC M01AA01) has analgesic, antipyretic, and anti-inflammatory properties. The effects are due to inhibition of cyclooxygenase and reduced prostaglandin synthesis. Phenylbutazone has a long half-life of 50 and 100 hours.
Indications
For the treatment of pain, fever, and inflammatory conditions, such as rheumatic diseases. As a veterinary drug, phenylbutazone is commonly used in horses.
Contraindications
Full details of precautions and interactions can be found in the drug label.
Adverse effects
The most common possible adverse effects include digestive problems such as nausea, diarrhea, and blood loss that may cause anemia, water retention, allergic reactions, headache, dizziness, fatigue, agitation, irritability, and insomnia. Rarely, severe blood formation disorders such as agranulocytosis are possible.
