AbButazone Phenylbutazone Dosage for Equine – How to Use It Phenylbutazone (Bute) is an analgesic and anti inflammatory medication used in horses for their treatment of lameness. This belongs to a group of drugs named non-steroidal anti-inflammatory drugs. Bute is a common medication recommended to horses. So horse owners should be knowing its advantages and disadvantages. Horse owners should wash their hands immediately after administering as this medicine can cause bone marrow, renal cardiovascular and gastrointestinal side effects.