21 CFR § 524.1600b - Nystatin, neomycin, thiostrepton, and triamcinolone ophthalmic ointment.

---
identifier: "/us/cfr/t21/s524.1600b"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "21 CFR § 524.1600b - Nystatin, neomycin, thiostrepton, and triamcinolone ophthalmic ointment."
title_number: 21
title_name: "Food and Drugs"
section_number: "524.1600b"
section_name: "Nystatin, neomycin, thiostrepton, and triamcinolone ophthalmic ointment."
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"
---


# 524.1600b Nystatin, neomycin, thiostrepton, and triamcinolone ophthalmic ointment.

(a) *Specifications.* Each cubic centimeter of ointment contains: 100,000 units of nystatin, neomycin sulfate equivalent to 2.5 milligrams of neomycin base, 2,500 units of thiostrepton, and 1.0 milligram of triamcinolone acetonide.

(b) *Sponsor.* See No. 053501 in § 510.600(c) of this chapter.

(c) *Related tolerances.* See §§ 556.430 and 556.470 of this chapter.

(d) *Conditions of use*—(1) *Dogs and cats*—(i) *Amount.* Apply 1 drop of ointment to the affected eye(s) 2 or 3 times daily. Treatment may be continued for up to 2 weeks if necessary.

(ii) *Indications for use.* For use as an anti-inflammatory, antipruritic, antifungal (*Candida albicans*), and antibacterial ointment for local therapy in keratitis and conjunctivitis.

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

(2) *Cattle*—(i) *Amount.* Apply small line of ointment to the affected eye(s) once daily. Treatment may be continued for up to 2 weeks if necessary.

(ii) *Indications for use.* For infectious kerato-conjunctivitis (pinkeye).

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

[40 FR 13873, Mar. 27, 1975, as amended at 50 FR 41490, Oct. 11, 1985; 79 FR 10972, Feb. 27, 2014; 84 FR 32993, July 11, 2019]