21 CFR § 520.1921 - Prochlorperazine, isopropamide, and neomycin.

---
identifier: "/us/cfr/t21/s520.1921"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "21 CFR § 520.1921 - Prochlorperazine, isopropamide, and neomycin."
title_number: 21
title_name: "Food and Drugs"
section_number: "520.1921"
section_name: "Prochlorperazine, isopropamide, and neomycin."
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"
---


# 520.1921 Prochlorperazine, isopropamide, and neomycin.

(a) *Specifications.* Each capsule contains either:

(1) Capsule No. 1: 3.33 milligrams of prochlorperazine (as the dimaleate), 1.67 milligrams of isopropamide (as the iodide), and 25 milligrams of neomycin base (as the sulfate); or

(2) Capsule No. 3: 10 milligrams of prochlorperazine (as the dimaleate), 5 milligrams of isopropamide (as the iodide), and 75 milligrams of neomycin base (as the sulfate).

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

(c) *Conditions of use in dogs*—(1) *Amount.* Administer capsules orally twice daily to dogs as follows:

|  |  |  |
| --- | --- | --- |
| 10 to 20 | 1 |  |
| 20 to 30 | 2 |  |
| Over 30 | 3 | 1 |
| Over 60 |  | 2 |

(2) *Indications for use.* For the treatment infectious bacterial gastroenteritis associated with emotional stress.

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

[49 FR 14103, Apr. 10, 1984, as amended at 56 FR 50653, Oct. 8, 1991; 60 FR 55659, Nov. 2, 1995; 79 FR 28827, May 20, 2014]