Skip to content
LexBuild

21 CFR § 520.1805 - Piperazine phosphate with thenium closylate tablets. 

---
identifier: "/us/cfr/t21/s520.1805"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "21 CFR § 520.1805 - Piperazine phosphate with thenium closylate tablets."
title_number: 21
title_name: "Food and Drugs"
section_number: "520.1805"
section_name: "Piperazine phosphate with thenium closylate tablets."
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"
---

# 520.1805 Piperazine phosphate with thenium closylate tablets.

(a) *Specifications.* Each scored tablet contains the equivalent of 250 milligrams piperazine hexahydrate (as piperazine phosphate) and 125 milligrams thenium (as thenium closylate) or 500 milligrams piperazine hexahydrate (as piperazine phosphate) and 250 milligrams thenium (as thenium closylate).

(b) *Sponsor.* See No. 000061 in § 510.600(c) of this chapter.

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

Number of Tablets at Each of the Two Doses

| Animal weight (lb) | 375 mg | 750 mg |
| --- | --- | --- |
| 2 but less than 5 | ⁄ |  |
| 5 but less than 10 | 1 | ⁄ |
| 10 or heavier | 2 | 1 |

(2) *Indications for use.* For removal of immature (fourth stage larvae) and adult hookworms (*Ancylostoma caninum, A. braziliense,* and *Uncinaria stenocephala*) and ascarids (*Toxocara canis*) from weaned pups and adult dogs.

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

[43 FR 32747, July 28, 1978, as amended at 47 FR 55476, Dec. 10, 1982; 61 FR 8873, Mar. 6, 1996; 62 FR 61625, Nov. 19, 1997; 78 FR 28826, May 20, 2014]