Commonly known as “bute” or simply PBZ, phenylbutazone is one of the oldest known nonsteroidal anti-inflammatory drugs (NSAIDs), second only to aspirin (Soma). Phenylbutazone was originally marketed for human use to relieve gout, gouty arthritis, rheumatism, and various other rheumatoid disorders, and the first studies published in the 1950s confirmed its effectiveness in human applications ("phenylbutazone."). However, after phenylbutazone was found to cause bone marrow depression, blood disorders, and cancer, it was discontinued for human use in the United States, but remains one of the most commonly prescribed NSAIDs in equine veterinary medicine today (Papich, Soma ). Additionally, PBZ is labeled as an analgesic/. antipyretic anti-inflammatory indicated for dogs, cattle and pigs with documented extra-label use in rabbits, elephants and other animals for musculoskeletal pain/inflammation, arthritis and soft tissue injuries (Plumb, Mikota, Papich). Phenylbutazone is also recognized. such as butadiene, phenylbutazone, bute, phenylbutzaone or phenylbute and is available from numerous manufacturers as tablets (1 g, 100 mg, 200 mg), paste (6 g or 12 g), powder (1 g in 10 g of powder for mixing in the feed ) and in solution (200 mg/mL in 100 mL vials) (Plumb, Papich). Oral administration is the most common route of administration, although the intravenous route is also used; PBZ should never be administered intramuscularly or subcutaneously because the substance is extremely irritating to tissues and can cause swelling, desquamation and necrosis (Plumb). When taken orally, phenylbutazone is absorbed through the stomach and small intestine; in equines it binds plasma up to 99%, which means it passes through...... the center of the paper....... Louis, MO: Elsevier Saunders, 2011. 605-07. Print."Phenylbutazone." Official FDA information, side effects and uses. Drugs.com and Web. November 15, 2013. "Phenylbutazone in Horses - Vets." Product safety information. FDA Center for Veterinary Medicine, October 14, 2009. Web. November 6, 2013. Plumb, Donald C., Pharm.D. "Phenylbutazone." Plumb's Handbook of Veterinary Drugs. 7th ed. Ames, IA: Wiley-Blackwell, 2011. 811-13. Print.Raeeszadeh, Mahdeih, Hamidreza Fattahian, Hamid Rajaian and Shahabeddin Safi. "Interaction between phenylbutazone and sodium thiopental in female stray dogs: the effect on recovery from anesthesia". Kafkas Universitesi Veteriner Fakultesi Dergisi 19.5 (2013): 780-82. Print.Soma, LR, CE Uboh, and GM Maylin. "The use of phenylbutazone in the horse." The Journal of Veterinary Pharmacology and Therapeutics 35 (2011): 1-12. Press.