(Henry Schein Animal Health) Phenylbutazone Paste is used for the management of inflammatory conditions in horses. Each 60 gram tube contains 20 grams of phenylbutazone. Phenylbutazone Paste is given orally. The recommended dosage of Phenylbutazone Paste is 1-2 grams per 500 lbs. body weight daily, not to exceed 4 gm daily. It is usually recommended that a relatively high dose is given for the first 48 hours, and then reduced gradually to a maintenance dose.