21 CFR § 524.1146 - Imidacloprid and moxidectin.

---
identifier: "/us/cfr/t21/s524.1146"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "21 CFR § 524.1146 - Imidacloprid and moxidectin."
title_number: 21
title_name: "Food and Drugs"
section_number: "524.1146"
section_name: "Imidacloprid and moxidectin."
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: "524"
part_name: "OPHTHALMIC AND TOPICAL 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 13873, Mar. 27, 1975, unless otherwise noted."
cfr_part: "524"
---


# 524.1146 Imidacloprid and moxidectin.

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

(1) 100 milligrams (mg) imidacloprid and 25 mg moxidectin; or

(2) 100 mg imidacloprid and 10 mg moxidectin.

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

(1) Nos. 017030, 051072, 051311, 055529, 058198, and 061133for use of product described in paragraph (a)(1) of this section as in paragraph (d)(1) of this section.

(2) Nos. 017030, 051072, 051311, 055529, 058198, and 061133 for use of product described in paragraph (a)(2) of this section as in paragraph (d)(2) of this section.

(3) Nos. 051072, 055529, 058198, 061133, and 061651 for use of product described in paragraph (a)(2) of this section as in paragraph (d)(3) of this section.

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

(d) *Conditions of use*—(1) *Dogs*—(i) *Amount.* Topically apply 4.5 mg/lb body weight (10 mg/kg) imidacloprid and 1.1 mg/lb (2.5 mg/kg) moxidectin, once a month.

(ii) *Indications for use.* (A) For the prevention of heartworm disease caused by *Dirofilaria immitis*; and the treatment and control of intestinal roundworms (*Toxocara canis* and *Toxascaris leonina*), hookworms (*Ancylostoma caninum* and *Uncinaria stenocephala*), and whipworms (*Trichuris vulpis*); kills adult fleas and treats flea infestations (*Ctenocephalides felis*).

(B) For treatment of *Dirofilaria immitis* circulating microfilariae in heartworm-positive dogs and the treatment and control of sarcoptic mange caused by *Sarcoptes scabiei* var. *canis.*

(2) *Cats*—(i) *Amount.* Topically apply 4.5 mg/lb body weight (10 mg/kg) imidacloprid and 0.45 mg/lb (1.0 mg/kg) moxidectin, once a month.

(ii) *Indications for use.* For the prevention of heartworm disease caused by *Dirofilaria immitis*; for the treatment and control of ear mite (*Otodectes cynotis*) infestations, intestinal roundworms (*Toxocara cati*), and hookworms (*Ancylostoma tubaeforme*); kills adult fleas and treats flea infestations (*Ctenocephalides felis*).

(3) *Ferrets*—(i) *Amount.* Topically apply 9.0 mg/lb body weight (20 mg/kg) imidacloprid and 0.9 mg/lb (2 mg/kg) moxidectin, once a month.

(ii) *Indications for use.* For the prevention of heartworm disease caused by *Dirofilaria immitis*; kills adult fleas (*Ctenocephalides felis*) and is indicated for the treatment of flea infestations on ferrets.

[72 FR 10597, Mar. 9, 2007, as amended at 78 FR 73698, Dec. 9, 2013; 85 FR 18120, Apr. 1, 2020; 86 FR 13185, Mar. 8, 2021; 86 FR 14821, Mar. 19, 2021; 87 FR 17946, Mar. 29, 2022; 87 FR 58963, Sept. 29, 2022; 88 FR 27700, May 3, 2023; 89 FR 14410, Feb. 27, 2024; 90 FR 40970, Aug. 22, 2025]