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U.S. Department of Health and Human Services

Animal & Veterinary

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ANADA 200-126 Phenylbutazone 20% Injection - supplemental approval (September 6, 1996)

Approval Date: September 6, 1996


Sponsor:Phoenix Scientific, Inc.
3915 S. 48th St. Terrace
P.O. Box 6457
St. Joseph, MO 64506-0457
Generic Name:phenylbutazone, USP
Trade Name:Phenylbutazone 20% Injection
Marketing Status:Prescription
Effect of Supplement:This supplemental application amends the ANADA to provide for the use of Phenylbutazone 20% Injection for the relief of inflammatory conditions associated with the musculoskeletal system in dogs. Phenylbutazone 20% Injection (ANADA 200-126) is currently approved for the same indication in horses.



For relief of inflammatory conditions associated with the musculoskeletal system in dogs and horses.



B.ROUTE OF ADMINISTRATIONIntravenous injection
 Horses1 to 2 g per 1000 lb body weight (5 to 10 mL/1000 lb) daily for a maximum of 5 days.Intravenous treatment may be followed by oral phenylbutazone dosage forms.
 Dogs10 mg per lb of body weight (0.5 mL/10 lbs), but not to exceed 800 mg (4 mL) daily regardless of weight.



Under the provisions of the Federal Food, Drug, and Cosmetic Act, as amended by the Generic Animal Drug and Patent Term Restoration Act (53 FR 50460, December 15, 1988; first GADPTRA Policy Letter), an Abbreviated New Animal Drug Application (ANADA) may be submitted for a generic version of an approved new animal drug (pioneer product). For certain dosage forms, the Agency grants a waiver from conducting an in vivo bioequivalence study (55 FR 24645, June 18, 1990; fifth GADPTRA Policy Letter). In lieu of bioequivalence testing, the safety and efficacy of the generic product are based on the demonstrated chemical equivalence to the pioneer product. Based on the formulation characteristics of the generic product, Phoenix Scientific, Inc. was granted a waiver April 15, 1992 (photocopy attached) from conducting an in vivo bioequivalence study with Phenylbutazone 20% Injection. The generic and pioneer products are solutions with the same concentrations of active and inactive ingredients.



Human Safety Relative to Food Consumption:
Data on human safety, pertaining to consumption of drug residues in food, were not required for approval of this NADA. This product is labeled as a prescription drug for use only in dogs, which are non-food animals.

Human Safety Relative to Possession, Handling and Administration:
Labeling contains adequate caution/warning statements.



This is a supplemental Abbreviated New Animal Drug Application (ANADA) filed under Section 512(b)(2) of the Federal, Food, Drug and Cosmetic (FFD&C) Act.

Safety and effectiveness for this generic animal drug, Phenylbutazone 20% Injection (200 mg/mL), were established by demonstration of chemical equivalence to the pioneer product, Cooper's Butazolidin® Injectable, 20% (NADA 011-575).

This generic product and the pioneer product have identical labeling indications for use in dogs. The route and method of administration of the two drugs are identical. Both drugs are administered intravenously. The generic and pioneer products contain the same active and inactive ingredients. Therefore, in compliance with FDA policy promulgated to implement Section 512(b)(2) of the FFD&C Act, no additional safety, efficacy, or in vivo bioequivalency studies were necessary or required.

The pioneer package insert includes recommendations for the drug's use in horses and dogs. The pioneer manufactured 100 mL vials for use in horses only. The pioneer also manufactured 25 and 50 mL size vials labeled for horses and dogs (vial sizes suitable for both species). Both species shared the same package insert.

The generic product 100 mL vial is labeled for use in horses only. The 100 mL vial for phenylbutazone is not suitable for use in dogs due to the large number of potential needle punctures in the vial stopper, and resulting stability/sterility concerns. Therefore, this supplement provides for the manufacture of 20 mL vials labeled for use in dogs and horses. The combined package insert for these vials is labeled for use in dogs and horses.

This supplemental ANADA satisfies the requirements of section 512 of the Act and demonstrates that Phenylbutazone 20% Injection, is safe and effective for its labeled indications when used under its proposed conditions of use.



  1. Photocopy of Waiver Letter.
  2. Generic Labeling:
    • package insert
    • immediate container label (20 mL vial)
    • shipping label
  3. Pioneer Labeling:
    • package insert
    • immediate container label
    • carton label

Copies of applicable labels may be obtained by writing to the:

Food and Drug Administration
Freedom of Information Staff (HFI-35)
5600 Fishers Lane
Rockville, MD 20857

Or requests may be sent via fax to: (301) 443-1726. If there are problems sending a fax, call (301) 443-2414.