Section 520.1720b - Phenylbutazone granules(a)Specifications. Each package of granules contains 1 or 8 grams of phenylbutazone.(b)Sponsors. See sponsors in § 510.600(c) of this chapter. (1) No. 000061 for 8-gram package.(2) No. 059320 for 1-gram package.(c)Conditions of use in horses - (1)Amount. Administer 1 to 2 grams per 500 pounds of body weight, not to exceed 4 grams, daily as required. by adding to a portion of the usual grain ration.(2)Indications for use. For the treatment of inflammatory conditions associated with the musculoskeletal system.(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. 78 FR 28826 , May 20, 2014