# Sulfadiazine/pyrimethamine suspension.
**AGENCY:**
Food and Drug Administration, HHS.
**ACTION:**
Final rule.
**SUMMARY:**
The Food and Drug Administration (FDA) is amending the animal drug regulations to reflect approval of a supplemental new animal drug application (NADA) filed by Animal Health Pharmaceuticals, LLC. The supplemental NADA provides for a revised human food safety warning on labeling for an oral suspension of sulfadiazine and pyrimethamine used for the treatment of equine protozoal myeloencephalitis (EPM).
**DATES:**
This rule is effective September 17, 2008.
**FOR FURTHER INFORMATION CONTACT:**
Melanie R. Berson, Center for Veterinary Medicine (HFV-110), Food and Drug Administration, 7500 Standish Pl., Rockville, MD 20855, 240-276-8337, e-mail: *[email protected]* .
**SUPPLEMENTARY INFORMATION:**
Animal Health Pharmaceuticals, LLC, 1805 Oak Ridge Circle, suite 101, St. Joseph, MO 64506, filed a supplement to NADA 141-240 for use of REBALANCE (sulfadiazine/pyrimethamine) Antiprotozoal Oral Suspension for the treatment of EPM caused by *Sarcocystis neurona* . The supplement provides for a revised human food safety warning on labeling. The supplemental NADA is approved as of August 27, 2008, and 21 CFR 520.2215 is amended to reflect the approval.
Approval of this supplemental NADA did not require review of additional safety or effectiveness data or information. Therefore, a freedom of information summary is not required.
The agency has determined under 21 CFR 25.33(a)(1) that this action is of a type that does not individually or cumulatively have a significant effect on the human environment. Therefore, neither an environmental assessment nor an environmental impact statement is required.
This rule does not meet the definition of “rule” in 5 U.S.C. 804(3)(A) because it is a rule of “particular applicability.” Therefore, it is not subject to the congressional review requirements in 5 U.S.C. 801-808.
**List of Subjects in 21 CFR Part 520**
Animal drugs.
**21 CFR Part 520**
Therefore, under the Federal Food, Drug, and Cosmetic Act and under authority delegated to the Commissioner of Food and Drugs and redelegated to the Center for Veterinary Medicine, 21 CFR part 520 is amended as follows:
**PART 520—ORAL DOSAGE FORM NEW ANIMAL DRUGS**
**21 CFR Part 520**
1. The authority citation for 21 CFR part 520 continues to read as follows:
**Authority:**
21 U.S.C. 360b.
**21 CFR Part 520**
2. In 520.2215, revise paragraph (c)(3) to read as follows:
§ 520.2215
(c) * * *
(3) *Limitations* . Do not use in horses intended for human consumption. Federal law restricts this drug to use by or on the order of a licensed veterinarian.
Dated: September 5, 2008.
William T. Flynn,
Acting Director, Center for Veterinary Medicine.