21 CFR § 520.1376 - Methimazole solution.

---
identifier: "/us/cfr/t21/s520.1376"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "21 CFR § 520.1376 - Methimazole solution."
title_number: 21
title_name: "Food and Drugs"
section_number: "520.1376"
section_name: "Methimazole solution."
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: "520"
part_name: "ORAL 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 13838, Mar. 27, 1975, unless otherwise noted."
cfr_part: "520"
---


# 520.1376 Methimazole solution.

(a) *Specifications.* Each milliliter of solution contains 5 milligrams (mg) methimazole.

(b) *Sponsor.* See No. 055529 in § 510.600(c) of this chapter.

(c) *Conditions of use in cats*—(1) *Amount.* Administer a starting dose of 2.5 mg every 12 hours. Following 3 weeks of treatment, the dose should be titrated to effect based on individual serum total T4 (TT4) levels and clinical response. Dose adjustments should be made in 2.5 mg increments with a maximum dosage of 20 mg per day divided, not to exceed 10 mg as a single dose.

(2) *Indications for use.* For the treatment of hyperthyroidism.

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

[89 FR 95103, Dec. 2, 2024]