21 CFR § 520.531 - Cythioate tablets.

---
identifier: "/us/cfr/t21/s520.531"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "21 CFR § 520.531 - Cythioate tablets."
title_number: 21
title_name: "Food and Drugs"
section_number: "520.531"
section_name: "Cythioate tablets."
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"
---


# 520.531 Cythioate tablets.

(a) *Specifications.* Each tablet contains 30 or 90 milligrams (mg) cythioate.

(b) *Sponsors.* See sponsor numbers in § 510.600(c) of this chapter as follows:

(1) No. 058198 for use of 30- and 90-mg tablets.

(2) No. 054771 for use of the 30-mg tablet.

(c) *Conditions of use*—(1) *Amount.* 30 milligrams cythioate per 20 pounds of body weight every third day or twice a week.

(2) *Indications for use.* Dogs, for control of fleas.

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

[49 FR 5615, Feb. 14, 1984, as amended at 59 FR 26942, May 25, 1994; 67 FR 78355, Dec. 24, 2002; 79 FR 28819, May 20, 2014; 86 FR 14818, Mar. 19, 2021]