---
kind: "section"
citation: "21 C.F.R. § 520.1900"
title: "21"
number: "520.1900"
heading: "Primidone."
url: "https://uscodex.org/cfr/21/520.1900"
---

# §520.1900. Primidone.

- (a) **Specifications.** Each tablet contains 50 or 250 milligrams of primidone.
- (b) **Sponsors.** See sponsor numbers in [§ 510.600(c)](/cfr/21/510.600.md?p=c) of this chapter.
  - (1) **No.** 069043 for use of 250 milligram tablets.
  - (2) **No.** 054771 for use of 50 and 250 milligram tablets.
- (c) **Conditions of use in dogs—**
  - (1) **Amount.** Twenty-five milligrams of primidone per pound of body weight (55 milligrams per kilogram of body weight) daily.
  - (2) **Indications for use.** For the control of convulsions associated with idiopathic epilepsy, epileptiform convulsions, viral encephalitis, distemper, and hardpad disease that occurs as a clinically recognizable lesion in certain entities in dogs.
  - (3) **Limitations.** Federal law restricts this drug to use by or on the order of a licensed veterinarian.

## Notes

### Amendments

[42 FR 61594, Dec. 6, 1977, as amended at 43 FR 55386, Nov. 28, 1978; 46 FR 8467, Jan. 27, 1981; 46 FR 57477, Nov. 24, 1981; 53 FR 40727, Oct. 18, 1988; 56 FR 37473, Aug. 7, 1991; 62 FR 35076, June 30, 1997; 78 FR 21060, Apr. 9, 2013; 79 FR 28827, May 20, 2014; 83 FR 48946, Sept. 28, 2018]

### Authority

Authority: 21 U.S.C. 360b.

### Source

Source: 40 FR 13838, Mar. 27, 1975, unless otherwise noted.

### Amendments

[42 FR 61594, Dec. 6, 1977, as amended at 43 FR 55386, Nov. 28, 1978; 46 FR 8467, Jan. 27, 1981; 46 FR 57477, Nov. 24, 1981; 53 FR 40727, Oct. 18, 1988; 56 FR 37473, Aug. 7, 1991; 62 FR 35076, June 30, 1997; 78 FR 21060, Apr. 9, 2013; 79 FR 28827, May 20, 2014; 83 FR 48946, Sept. 28, 2018]