Section 520.1720d - Phenylbutazone gel(a)Specifications. Each 30 grams of gel contains 4 grams of phenylbutazone.(b)Sponsor. See No. 061133 in § 510.600(c) of this chapter. require bioequivalency and safety information.(c)Conditions of use in horses -(1)Amount. 1 to 2 grams of phenylbutazone per 500 pounds of body weight, not to exceed 4 grams daily.(2)Indications for use. For relief of inflammatory conditions associated with the musculoskeletal system of horses.(3)Limitations. Do not use in horses intended for human consumption. Federal law prohibits the use of this drug in female dairy cattle 20 months of age or older. Federal law restricts this drug to use by or on the order of a licensed veterinarian.50 FR 13561, Apr. 5, 1985, as amended at 50 FR 49372, Dec. 2, 1985; 55 FR 8462, Mar. 8, 1990; 66 FR 14073, Mar. 9, 2001; 68 FR 4915, Jan. 31, 2003; 78 FR 28826, May 20, 2014; 84 FR 8973, Mar. 13, 2019