21 CFR § 520.260 - -Butyl chloride.

---
identifier: "/us/cfr/t21/s520.260"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "21 CFR § 520.260 - -Butyl chloride."
title_number: 21
title_name: "Food and Drugs"
section_number: "520.260"
section_name: "-Butyl chloride."
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"
---


# 520.260 -Butyl chloride.

(a) *Specifications.* Each capsule contains 221, 442, 884, or 1,768 milligrams (mg); or 4.42 grams of *n*-butyl chloride.

(b) *Sponsors.* See sponsors in § 510.600(c) of this chapter:

(1) No. 023851 for capsules containing 221, 442, 884, or 1,768 mg, or 4.42 grams (g); and

(2) No. 054771 for capsules containing 221 mg.

(c) *Conditions of use in dogs*—(1) *Amount.* Administer capsules orally based on body weight as follows:

(i) Capsules containing 221 mg: Under 5 pounds, 1 capsule per 1
1/4 pounds of body weight.

(ii) Capsules containing 442 mg: Under 5 pounds, 1 capsule per 2
1/2 pounds of body weight.

(iii) Capsules containing 884 mg:

(A) Under 5 pounds, 1 capsule;

(B) 5 to 10 pounds, 2 capsules;

(C) 10 to 20 pounds, 3 capsules;

(D) 20 to 40 pounds, 4 capsules;

(E) Over 40 pounds, 5 capsules.

(iv) Capsules containing 1,768 mg: Dogs weighing 5 to 10 pounds, 1 capsule.

(v) Capsules containing 4.42 g: Dogs weighing 40 pounds or over, 1 capsule.

(2) *Indications for use.* For the removal of ascarids (*Toxocara canis* and *Toxascaris leonina*) and hookworms (*Ancylostoma caninum, Ancylostoma braziliense,* and *Uncinaria stenocephala*) from dogs.

(3) *Limitations.* Dogs should not be fed for 18 to 24 hours before being given the drug. Administration of the drug should be followed in 
1/2 to 1 hour with a mild cathartic. Normal feeding may be resumed 4 to 8 hours after treatment. Animals subject to reinfection may be retreated in 2 weeks. A veterinarian should be consulted before using in severely debilitated dogs.

[86 FR 10819, Feb. 23, 2021]