Description:
Active Ingredients:
Each tablet contains:
Each mL contains:
| Phenylbutazone |
200 mg |
| Benzyl alcohol
(as preservative) |
1.5% |
Also contains sodium hydroxide to adjust pH and
water for injection, U.S.P.
Indications:
PHENYLBUTAZONE is used for
the relief of inflammatory conditions associated with the musculoskeletal system
in horses.
Pharmacology:
PHENYLBUTAZONE is the accepted generic
name of the drug known chemically as 4-butyl-1,2-diphenyl-3,5-pyrazolidinedione.
It has the following chemical structure.
Phenylbutazone is a white crystalline solid,
slightly soluble in water, and soluble in some organic solvents. It has no odor
and a slightly bitter taste.
Phenylbutazone is a nonhormonal, anti-inflammatory agent. It is unrelated to the
corticosteroid anti-inflammatory agents. The anti-inflammatory activity of
phenylbutazone has been shown in lower animals1 and in man.2 The greatest amount
of data on efficacy is in man.3-6 Studies in horses have reported useful
anti-inflammatory activity.7-10 Metabolic studies in horses have shown that the
drug is well absorbed when administered orally with a balling gun. The apparent
half-life is 3.5 hours.
Dosage and Administration:
Tablets: The oral dose for horses is two
(2) to four (4) tablets (2 to 4 g) per 1,000 lbs. of body weight per day. The
total daily dose should be limited to four (4) tablets per day. Because of the
relatively short half-life of the drug, administration every eight (8) hours is
the most satisfactory schedule.
Injection: The intravenous dose for horses is 5 to 10 mL (1 to 2 g) per 1,000 lbs.
of body weight per day. The injection should be administered slowly. Intravenous
administration should be limited to five (5) consecutive days. An initial high
dose is recommended to obtain a prompt effect. As the symptoms regress, the dose
should be reduced.
The response to phenylbutazone is usually prompt. If there is not a significant
clinical effect in five (5) days, a re-evaluation of the diagnosis and treatment
should be made.
Contraindications:
Use with caution in patients who have a
history of drug allergy.
Precautions:
Store the product in a cool place (46°
to 59°F) or alternatively store in a refrigerator.
Cautions:
Federal (USA) law restricts this
drug to use by or on the order of a licensed veterinarian.
Keep out of the reach of children.
In the treatment of inflammatory conditions associated with infections, specific
anti-infective therapy is required.
Warnings:
Not for use in horses intended for food.
Side Effects:
Doses of phenylbutazone higher than those
recommended have been shown to produce intestinal ulcerative lesions.12
Necrotizing phlebitis in the portal vein has been observed in horses receiving
high doses for extended periods of time.
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