21 CFR § 520.1341 - Megestrol.

---
identifier: "/us/cfr/t21/s520.1341"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "21 CFR § 520.1341 - Megestrol."
title_number: 21
title_name: "Food and Drugs"
section_number: "520.1341"
section_name: "Megestrol."
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"
---


# 520.1341 Megestrol.

(a) *Specifications.* Each tablet contains 5 or 20 milligrams of megestrol acetate.

(b) *Sponsor.* See No. 000061 in § 510.600(c) of this chapter.

(c) *Conditions of use in dogs*—(1) *Amount.* Administer orally, intact, or crushed and mixed with food as follows:

(i) For the postponement of estrus by proestrus treatment: 1 milligram per pound of body weight per day for 8 days.

(ii) For the postponement of estrus by anestrus treatment: 0.25 milligram per pound of body weight per day for 32 days.

(iii) For alleviation of false pregnancy: 1 milligram per pound of body weight per day for 8 days.

(2) *Indications for use.* For the postponement of estrus and the alleviation of false pregnancy in female dogs.

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

[40 FR 13838, Mar. 27, 1975, as amended at 52 FR 7832, Mar. 13, 1987; 78 FR 28824, May 20, 2014]