Section 520.1100 - Griseofulvin(a)Specifications.(1) The powder complies with U.S.P. for griseofulvin, microsize.(2) Each bolus contains 2.5 grams griseofulvin.(3) Each tablet contains 125 or 500 milligrams griseofulvin.(b)Sponsors. See sponsors in § 510.600(c) of this chapter.(1) No. 000061 for use of products described in paragraph (a) for use as in paragraph (d) of this section.(2) No. 061133 for use of the powder described in paragraph (a)(1) for use as in paragraphs (d)(1)(i)(A) and (d)(1)(ii) of this section.(c)Special considerations. Federal law restricts this drug to use by or on the order of a licensed veterinarian.(d)Conditions of use -(1)Horses -(i)Amount and indications for use.(A) For equine ringworm infection caused by Trichophyton equinum or Microsporum gypseum, administer soluble powder described in paragraph (a)(1) of this section daily as a drench or as a top dressing on feed for not less than 10 days as follows: adults, 2.5 grams; yearlings, 1.25 to 2.5 grams; and foals, 1.25 grams.(B) For treating ringworm infection caused by T. equinum, administer boluses described in paragraph (a)(2) of this section daily for not less than 10 days as follows: adults, 1 bolus; yearlings, one-half to 1 bolus; and foals, one-half bolus.(ii)Limitations. Do not use in horses intended for human consumption.(2) Dogs and cats: (i)Amount. 125- and 500-milligram tablets administered orally as follows: (A) Daily (single or divided) dose as follows: For animals weighing up to 6 pounds: 62.5 milligrams; for animals weighing 6 to 18 pounds: 125 milligrams; for animals weighing 18 to 36 pounds: 250 milligrams; for animals weighing 36 to 48 pounds: 375 milligrams; for animal weighing 48 to 75 pounds: 500 milligrams.(B) Weekly (single) dose: If experience indicates that treatment is more effective for the drug given in large doses, administer at intervals of 7 to 10 days, a dose equal to 10 milligrams/pound of body weight * body weight * number of days between treatments. Dosage should be adjusted according to response. Administer additional dose after the animal is free of infection.(ii)Indications for use. For treatment of fungal infections of the skin, hair, and claws caused by Trichophyton mentagrophytes, T. rubrum, T. schoenleini, T. sulphurem, T. verrucosum, T. interdigitale, Epidermophyton floccosum, Microsporum gypseum, M. canis, M. audouini.40 FR 13838, Mar. 27, 1975, as amended at 41 FR 42948, Sept. 29, 1976; 43 FR 28458, June 30, 1978; 52 FR 7832, Mar. 13, 1987; 54 FR 30205, July 19, 1989; 71 FR 38073 , July 5, 2006; 77 FR 28253 , May 14, 2012; 78 FR 28822 , May 20, 2014; 84 FR 8972 , Mar. 13, 2019