(Phoenix Pharmaceutical) Phenylbute Powder is for the relief of inflammatory conditions associated with the musculoskeletal system in horses. Phenylbute Powder is a non-steroidal anti-inflammatory drug (NSAID). Phenylbute Powder contains phenylbutazone. Each 10 grams of powder (1 level scoop) contain 1 gram of phenylbutazone. The dosage of Phenylbute Powder is recommended at 1-2 scoops per 500 lbs body weight daily with feed. Phenylbutazone. Orange citrus flavor.