21 CFR § 522.1362 - Melarsomine powder for injection.

---
identifier: "/us/cfr/t21/s522.1362"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "21 CFR § 522.1362 - Melarsomine powder for injection."
title_number: 21
title_name: "Food and Drugs"
section_number: "522.1362"
section_name: "Melarsomine powder for injection."
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"
---


# 522.1362 Melarsomine powder for injection.

(a) *Specifications.* The drug consists of a vial of lyophilized powder containing 50 milligrams of melarsomine dihydrochloride which is reconstituted with the provided 2 milliliters of sterile water for injection.

(b) *Sponsor.* See Nos. 000010 and 086073 in § 510.600(c) of this chapter.

(c) *Conditions of use*—(1) *Amount.* Administer only by deep intramuscular injection in the lumbar muscles (L<sub>3</sub>-L<sub>5</sub>).

(2) *Indications.* Treatment of stabilized, class 1, 2, and 3 heartworm disease (asymptomatic to mild, moderate, and severe, respectively) caused by immature (4 month-old, stage L<sub>5</sub>) to mature adult infections of *Dirofilaria immitis* in dogs.

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

[60 FR 49340, Sept. 25, 1995, as amended at 79 FR 16191, Mar. 25, 2014; 82 FR 21690, May 10, 2017; 84 FR 39184, Aug. 9, 2019]