21 CFR § 520.1630 - Oxfendazole suspension.

---
identifier: "/us/cfr/t21/s520.1630"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "21 CFR § 520.1630 - Oxfendazole suspension."
title_number: 21
title_name: "Food and Drugs"
section_number: "520.1630"
section_name: "Oxfendazole 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"
---


# 520.1630 Oxfendazole suspension.

(a) *Specifications.* Each milliliter of suspension contains:

(1) 90.6 milligrams (mg) oxfendazole (9.06 percent).

(2) 225.0 mg oxfendazole (22.5 percent).

(b) *Sponsor.* See Nos. 000010 and 054771 in § 510.600(c) of this chapter.

(c) *Related tolerances. See* § 556.495 of this chapter.

(d) *Special considerations.* See § 500.25 of this chapter. If labeled for administration by stomach tube: Federal law restricts this drug to use by or on the order of a licensed veterinarian.

(e) *Conditions of use*—(1) *Horses.* Use the product described in paragraph (a)(1) of this section as follows:

(i) *Amount.* 10 mg per kilogram (/kg) of body weight by stomach tube or dose syringe. Horses maintained on premises where reinfection is likely to occur should be retreated in 6 to 8 weeks.

(ii) *Indications for use.* For removal of large roundworms (*Parascaris equorum*), mature and 4th stage larvae pinworms (*Oxyuris equi*), large strongyles (*Strongylus edentatus, S. vulgaris,* and *S. equinus*), and small strongyles.

(iii) *Limitations.* Withholding feed or water prior to use is unnecessary. Administer drug with caution to sick or debilitated horses. Do not use in horses intended for human consumption.

(2) *Cattle.* Use the products described in paragraphs (a)(1) and (a)(2) of this section as follows:

(i) *Amount.* 4.5 mg/kg of body weight by dose syringe. Treatment may be repeated in 4 to 6 weeks.

(ii) *Indications for use.* For the removal and control of: lungworms (*Dictyocaulus viviparus*—adult, L4); stomach worms: barberpole worms (*Haemonchus contortus* and *H. placei*—adult), small stomach worms (*Trichostrongylus axei*—adult), brown stomach worms (*Ostertagia ostertagi*—adult, L4, inhibited L4); intestinal worms; nodular worms (*Oesophagostomum radiatum*—adult), hookworms (*Bunostomum phlebotomum*—adult), small intestinal worms (*Cooperia punctata, C. oncophora,* and *C. surnabada*—adult, L4), and tapeworms (*Moniezia benedeni*—adult).

(iii) *Limitations.* Cattle must not be slaughtered until 7 days after treatment. Because a withdrawal time in milk has not been established, do not use in female dairy cattle of breeding age.

[55 FR 46943, Nov. 8, 1990, as amended at 56 FR 8710, Mar. 1, 1991; 61 FR 5506, Feb. 13, 1996; 72 FR 10596, Mar. 9, 2007; 73 FR 45610, Aug. 6, 2008; 75 FR 10166, Mar. 5, 2010; 78 FR 28825, May 20, 2014]