StacksVerified U.S. regulatory reference

21 CFR §520.1900

Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗
  1. (a)Specifications. Each tablet contains 50 or 250 milligrams of primidone.
  2. (b)Sponsors. See sponsor numbers in § 510.600(c) of this chapter.
    1. (1)No. 069043 for use of 250 milligram tablets.
    2. (2)No. 054771 for use of 50 and 250 milligram tablets.
  3. (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.
    1. (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.
    2. (3)Limitations. Federal law restricts this drug to use by or on the order of a licensed veterinarian.