21 CFR § 526.1810 - Pirlimycin.

---
identifier: "/us/cfr/t21/s526.1810"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "21 CFR § 526.1810 - Pirlimycin."
title_number: 21
title_name: "Food and Drugs"
section_number: "526.1810"
section_name: "Pirlimycin."
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: "526"
part_name: "INTRAMAMMARY 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."
cfr_part: "526"
---


# 526.1810 Pirlimycin.

(a) *Specifications.* Each single-dose, 10-milliliter syringe contains 50 milligrams (mg) of pirlimycin (as pirlimycin hydrochloride).

(b) *Sponsor.* See No. 054771 in § 510.600(c) of this chapter.

(c) *Related tolerances.* See § 556.515 of this chapter.

(d) *Conditions of use in lactating cows*—(1) *Amount.* Infuse the contents of one syringe (50 mg pirlimycin) into each infected quarter. Daily treatment may be repeated at 24-hour intervals for up to 8 consecutive days.

(2) *Indications for use.* For the treatment of clinical and subclinical mastitis in lactating dairy cattle associated with *Staphylococcus* species such as *Staphylococcus aureus* and *Streptococcus* species such as *Streptococcus agalactiae*, *Streptococcus dysgalactiae*, and *Streptococcus uberis.*

(3) *Limitations.* Milk taken from animals during treatment and for 36 hours following the last treatment must not be used for food regardless of treatment duration. Following infusion twice at a 24-hour interval, treated animals must not be slaughtered for 9 days. Following any extended duration of therapy (infusion longer than twice at a 24-hour interval, up to 8 consecutive days), animals must not be slaughtered for 21 days. Federal law restricts this drug to use by or on the order of a licensed veterinarian.

[58 FR 58486, Nov. 2, 1993, as amended at 65 FR 61091, Oct. 16, 2000; 73 FR 811, Jan. 4, 2008; 79 FR 10973, Feb. 27, 2014; 86 FR 13188, Mar. 8, 2021]