21 CFR § 522.2474 - Tolazoline.

---
identifier: "/us/cfr/t21/s522.2474"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "21 CFR § 522.2474 - Tolazoline."
title_number: 21
title_name: "Food and Drugs"
section_number: "522.2474"
section_name: "Tolazoline."
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: "522"
part_name: "IMPLANTATION OR INJECTABLE 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 13858, Mar. 27, 1975, unless otherwise noted."
cfr_part: "522"
---


# 522.2474 Tolazoline.

(a) *Specifications.* Each milliliter of solution contains tolazoline hydrochloride equivalent to 100 milligrams (mg) of base activity.

(b) *Sponsor.* See No. 059399 in § 510.600(c) of this chapter.

(c) *Conditions of use in horses*—(1) *Amount.* Administer slowly by intravenous injection 4 mg per kilogram of body weight or 1.8 mg per pound (4 milliliters (mL) per 100 kilograms or 4 mL per 220 pounds).

(2) *Indications for use.* For use in horses when it is desirable to reverse the effects of sedation and analgesia caused by xylazine.

(3) *Limitations.* Do not use in horses intended for human consumption. Federal law restricts this drug to use by or on the order of a licensed veterinarian.

[79 FR 16197, Mar. 25, 2014, as amended at 79 FR 74020, Dec. 15, 2014; 80 FR 13230, Mar. 13, 2015]