21 CFR § 520.2220b - Sulfadimethoxine suspension.

---
identifier: "/us/cfr/t21/s520.2220b"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "21 CFR § 520.2220b - Sulfadimethoxine suspension."
title_number: 21
title_name: "Food and Drugs"
section_number: "520.2220b"
section_name: "Sulfadimethoxine suspension."
chapter_name: "FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES"
subchapter_number: "E"
subchapter_name: "ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS"
part_number: "520"
part_name: "ORAL DOSAGE FORM NEW ANIMAL DRUGS"
positive_law: false
currency: "2026-04-05"
last_updated: "2026-04-05"
format_version: "1.1.0"
generator: "[email protected]"
authority: "21 U.S.C. 360b."
regulatory_source: "40 FR 13838, Mar. 27, 1975, unless otherwise noted."
cfr_part: "520"
---


# 520.2220b Sulfadimethoxine suspension.

(a) *Specifications.* Each milliliter of suspension contains 50 milligrams (mg) sulfadimethoxine.

(b) *Sponsors.* See Nos. 000061 and 054771 in § 510.600(c) of this chapter.

(c) *Conditions of use in dogs and cats*—(1) *Amount.* Administer orally 25 mg per pound of body weight, followed by 12.5 mg per pound of body weight daily until the animal is free of clinical signs for 48 hours.

(2) *Indications for use.* For the treatment of sulfadimethoxine-susceptible bacterial infections in dogs and cats and enteritis associated with coccidiosis in dogs.

(3) *Limitations.* Federal law restricts this drug to use by or on the order of a licensed veterinarian.

[79 FR 28829, May 20, 2014, as amended at 88 FR 55564, Aug. 16, 2023]