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21 CFR § 558.300 - Ivermectin.

---
identifier: "/us/cfr/t21/s558.300"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "21 CFR § 558.300 - Ivermectin."
title_number: 21
title_name: "Food and Drugs"
section_number: "558.300"
section_name: "Ivermectin."
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: "558"
part_name: "NEW ANIMAL DRUGS FOR USE IN ANIMAL FEEDS"
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. 354, 360b, 360ccc, 360ccc-1, 371."
regulatory_source: "40 FR 13959, Mar. 27, 1975, unless otherwise noted."
cfr_part: "558"
---

# 558.300 Ivermectin.

(a) *Specifications.* Type A medicated article containing 2.72 grams ivermectin per pound (g/lb).

(b) *Sponsor.* See No. 000010 in § 510.600(c) of this chapter.

(c) *Related tolerances.* See § 556.344 of this chapter.

(d) *Special considerations.* See § 500.25 of this chapter.

(e) *Conditions of use in swine.* It is used in feed as follows:

| Ivermectin ingrams/ton | Combination in grams/ton | Indications for use | Limitations | Sponsor |
| --- | --- | --- | --- | --- |
| (1) 1.8 |  | Weaned, growing-finishing swine: For treatment and control of gastrointestinal roundworms ( adults and fourth-stage larvae;  adults;  adults and fourth-stage larvae;  spp., adults and fourth-stage larvae); kidneyworms ( adults and fourth-stage larvae); lungworms ( spp., adults); threadworms ( adults and somatic larvae); lice (); and mange mites ( var. ) | Feed as the only feed for 7 consecutive days to provide 0.1 milligrams per kilograms (mg/kg) of body weight per day. Withdraw 5 days before slaughter | 000010 |
| (2) 1.8 | Bacitracin methylenedisalicylate, 10 to 30 | Weaned, growing-finishing swine: For treatment and control of gastrointestinal roundworms ( adults and fourth-stage larvae;  adults;  adults and fourth-stage larvae;  spp., adults and fourth-stage larvae); kidneyworms ( adults and fourth-stage larvae); lungworms ( spp., adults); threadworms ( adults and somatic larvae); lice (); and mange mites (var. ); and for increased rate of weight gain and improved feed efficiency | Feed as the only feed for 7 consecutive days to provide 0.1 mg/kg of body weight per day. Withdraw 5 days before slaughter | 000010 |
| (3) 1.8 | Bacitracin methylenedisalicylate, 250 | Weaned, growing-finishing swine: For treatment and control of gastrointestinal roundworms ( adults and fourth-stage larvae;  adults;  adults and fourth-stage larvae;  spp., adults and fourth-stage larvae); kidneyworms ( adults and fourth-stage larvae); lungworms ( spp., adults); threadworms ( adults and somatic larvae); lice (); and mange mites ( var. ); and for control of swine dysentery associated with  on premises with a history of swine dysentery, but where symptoms have not yet occurred, or following an approved treatment of disease condition | Feed as the only feed for 7 consecutive days to provide 0.1 mg/kg of body weight per day. Withdraw 5 days before slaughter | 000010 |
| (4) 1.8 to 11.8 |  | Adult and breeding swine: For treatment and control of gastrointestinal roundworms ( adults and fourth-stage larvae;  adults;  adults and fourth-stage larvae;  spp., adults and fourth-stage larvae); kidneyworms ( adults and fourth-stage larvae); lungworms ( spp., adults); threadworms ( adults and somatic larvae, and prevention of transmission of infective larvae to piglets, via the colostrum or milk, when fed during gestation); lice (); and mange mites ( var. ) | Feed as the only feed for 7 consecutive days to provide 0.1 mg/kg of body weight per day. Withdraw 5 days before slaughter | 000010 |
| (5) 1.8 to 11.8 | Bacitracin methylenedisalicylate, 250 | Pregnant sows: For treatment and control of gastrointestinal roundworms ( adults and fourth-stage larvae;  adults;  adults and fourth-stage larvae;  spp., adults and fourth-stage larvae); kidneyworms ( adults and fourth-stage larvae); lungworms ( spp., adults); threadworms ( adults and somatic larvae, and prevention of transmission of infective larvae to piglets, via the colostrum or milk, when fed during gestation); lice (); and mange mites ( var. ); and for control of clostridial enteritis caused by  in suckling piglets | Feed as the only feed for 7 consecutive days to provide 0.1 mg/kg of body weight per day. Withdraw 5 days before slaughter. Feed bacitracin methylenedisalicylate Type C medicated feed to sows from 14 days before through 21 days after farrowing on premises with a history of clostridial scours | 000010 |
| (6) 18.2 to 120 |  | Adult and breeding swine: For treatment and control of gastrointestinal roundworms ( adults and fourth-stage larvae;  adults;  adults and fourth-stage larvae;  spp., adults and fourth-stage larvae); kidneyworms ( adults and fourth-stage larvae); lungworms ( spp., adults); threadworms ( adults and somatic larvae, and prevention of transmission of infective larvae to piglets, via the colostrum or milk, when fed during gestation); lice (); and mange mites ( var. ) | Top dress on daily ration for individual treatment for 7 consecutive days to provide 0.1 mg/kg of body weight per day. Withdraw 5 days before slaughter | 000010 |

[72 FR 37437, July 10, 2007, as amended at 81 FR 17609, Mar. 30, 2016; 81 FR 95005, Dec. 27, 2016; 84 FR 12499, Apr. 2, 2019; 84 FR 39185, Aug. 9, 2019]