Phenylbutazone
Generic name: Phenylbutazone injection
Dosage form: FOR ANIMAL USE ONLY
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CAUTION: Federal law restricts this drug to use by or on the order of a licensed veterinarian.
KEEP OUT OF REACH OF CHILDREN
FOR HORSES ONLY.
DESCRIPTION: Phenylbutazone 20% Injection (Phenylbutazone) is a synthetic, nonhormonal anti-inflammatory, antipyretic compound useful in the management of inflammatory conditions. The apparent analgesic effect is probably related mainly to the compound's anti-inflammatory properties. Chemically, Phenylbutazone is 4-butyl-1,2-diphenyl-3,5-pyrazolidinedione. It is a pyrazolon derivative entirely unrelated to the steroid hormones, and has the following structural formula:
BACKGROUND PHARMACOLOGY
Kuzell, 1, 2, 3 Payne,4 Fleming,5 and Denko6 demonstrated clinical effectiveness of Phenylbutazone in acute rheumatism, gout, gouty arthritis and various other rheumatoid disorders in man. Anti-rheumatic and anti-inflammatory activity has been well established by Fabre,7 Domenjoz,8 Wilhelmi,9 and Yourish.10 Lieberman 11 reported on the effective use of Phenylbutazone in the treatment of painful conditions of the musculoskeletal system in dogs; including posterior paralysis associated with intervertebral disc syndrome, painful fractures, arthritis, and painful injuries to the limbs and joints. Joshua12 observed objective improvement without toxicity following long-term therapy of two aged arthritic dogs. Ogilvie and Sutter13 reported rapid response to Phenylbutazone therapy in a review of 19 clinical cases including posterior paralysis, posterior weakness, arthritis, rheumatism, and other conditions associated with lameness and musculoskeletal weakness.
Camberos14 reported favorable results with Phenylbutazone following intermittent treatment of Thoroughbred horses for arthritis and chronic arthrosis (e.g., osteoarthritis of medial and distal bones of the hock, arthritis of stifle and hip, arthrosis of the spine, chronic hip pains, achronic pain in the trapezius muscles, and generalized arthritis). Results were less favorable in cases of traumatism, muscle rupture, strains and inflammations of the third phalanx. Sutter15 reported favorable response in chronic equine arthritis, fair results in a severely bruised mare, and poor results in two cases where the condition was limited to the third phalanx
