StacksVerified U.S. regulatory reference

21 CFR §520.1375

Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗
  1. (a)Specifications. Each tablet contains 2.5 or 5 milligrams (mg) methimazole.
  2. (b)Sponsors, See Nos. 043264 and 086101in § 510.600 of this chapter.
  3. (c)Conditions of use in cats—(1) Amount. The starting dose is 2.5 mg every 12 hours. Following 3 weeks of treatment, the dose should be titrated to effect based on individual serum total T4 (TT4) levels and clinical response. Dose adjustments should be made in 2.5 mg increments. The maximum total dosage is 20 mg per day divided, not to exceed 10 mg as a single administration.
    1. (2)Indications for use. For the treatment of hyperthyroidism.
    2. (3)Limitations. Federal law restricts this drug to use by or on the order of a licensed veterinarian.