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→Phenylbutazone
Phenylbutazone (colloquially known as "bute") has a more potent anti-inflammatory than analgesic action. It follows the standard NSAID mechanism of COX inhibition, and concentrates in inflammatory exudates. It is cheap and commonly used in veterinary practice.
Phenylbutazone (colloquially known as "bute") has a more potent anti-inflammatory than analgesic action. It follows the standard NSAID mechanism of COX inhibition, and concentrates in inflammatory exudates. It is cheap and commonly used in veterinary practice.
Administration of phenylbutazone with food reduces the rate of absorption. Although the drug's bioavailability remains the same, it is absorbed further down the gastro-intestinal tract than normal and plasma levels rise more slowly. Rate of metabolism varies vastly between species, and in some species (for example, the dog) phenylbutzone displays zero-order kinetics.
Administration of phenylbutazone with food reduces the rate of absorption. Although the drug's bioavailability remains the same, it is absorbed further down the gastro-intestinal tract than normal and plasma levels rise more slowly. Rate of metabolism varies vastly between species, and in some species (for example, the dog) phenylbutzone displays [[Pharmacokinetics#Zero Order Kinetics|zero-order kinetics]].
Phenylbutazone has caused death by aplastic anaemia in man, and since safe milk and meat residue levels cannot be established, it is banned in food producing animals. Protein losing enteropathy has been seen in horses and ponies. The drug has a low safety margin and care must be taken in equids to use the lower end of the dose range. Top range doses would lead to accumulation and toxicity.
Phenylbutazone has caused death by aplastic anaemia in man, and since safe milk and meat residue levels cannot be established, it is banned in food producing animals. Protein losing enteropathy has been seen in horses and ponies. The drug has a low safety margin and care must be taken in equids to use the lower end of the dose range. Top range doses would lead to accumulation and toxicity.