Federal regulations · Through 2026-08-25 · Newer source version available

21 CFR 520.48: Altrenogest.

(a) Specifications. Each milliliter (mL) of solution contains 2.2 milligrams (mg) altrenogest.
(b) Sponsors. See sponsors in § 510.600(c) of this chapter:
(1) Nos. 000061 and 051072 for use as in paragraph (d) of this section.
(2) No. 061133 for use as in paragraph (d)(1) of this section.
(3) No. 053701 for use as in paragraph (d)(2) of this section.
(c) Tolerances. See § 556.36 of this chapter.
(d) Conditions of use—(1) Horses—(i) Amount. 1.0 mL per 110 pounds body weight (0.044 mg/kg) daily for 15 consecutive days.
(ii) Indications for use. For suppression of estrus in mares.
(iii) Limitations. Do not use in horses intended for human consumption. Federal law restricts this drug to use by or on the order of a licensed veterinarian.
(2) Swine—(i) Amount. Administer 6.8 mL (15 mg altrenogest) per gilt once daily for 14 consecutive days by top-dressing on a portion of each gilt's daily feed.
(ii) Indications for use. For synchronization of estrus in sexually mature gilts that have had at least one estrous cycle.
(iii) Limitations. Do not use in gilts having a previous or current history of uterine inflammation (i.e., acute, subacute or chronic endometritis). Gilts must not be slaughtered for human consumption for 21 days after the last treatment.

Where this section sits in the code

Title 21—Food and Drugs
CHAPTER I—FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES
SUBCHAPTER E—ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS
PART 520—ORAL DOSAGE FORM NEW ANIMAL DRUGS

(a) Specifications. Each milliliter (mL) of solution contains 2.2 milligrams (mg) altrenogest.

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

(1) Nos. 000061 and 051072 for use as in paragraph (d) of this section.

(2) No. 061133 for use as in paragraph (d)(1) of this section.

(3) No. 053701 for use as in paragraph (d)(2) of this section.

(d) Conditions of use—(1) Horses—(i) Amount. 1.0 mL per 110 pounds body weight (0.044 mg/kg) daily for 15 consecutive days.

(ii) Indications for use. For suppression of estrus in mares.

(iii) Limitations. Do not use in horses intended for human consumption. Federal law restricts this drug to use by or on the order of a licensed veterinarian.

(2) Swine—(i) Amount. Administer 6.8 mL (15 mg altrenogest) per gilt once daily for 14 consecutive days by top-dressing on a portion of each gilt's daily feed.

(ii) Indications for use. For synchronization of estrus in sexually mature gilts that have had at least one estrous cycle.

(iii) Limitations. Do not use in gilts having a previous or current history of uterine inflammation (i.e., acute, subacute or chronic endometritis). Gilts must not be slaughtered for human consumption for 21 days after the last treatment.

Collected 2026-08-27T02:24:47Z. Source file · JSON

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