03/02/2026
💊 It is Medicine Monday! And today we are going to cover, phenylbutazone (Bute) and firocoxib (Equioxx and Equicoxib), two common non-steroidal anti-inflammatory drugs or commonly referred to as the acronym NSAID’s. NSAID’s act by inhibiting a class of enzymes called cyclooxygenase (COX). COX enzymes are involved in the inflammatory process which are responsible for inflammation, pain and fever.
💊 What is the history of bute?
Believe it or not in the early 1950s, bute was actually a medication prescribed for humans with rheumatoid arthritis; however, due to the dangerous side effects and more effective less dangerous medications on the market phenylbutazone fell out of favor. Around the same time, veterinary medicine administered bute to treat lameness in horses due to it being affordable, easy to administer and minimal side effects.
💊 What is bute prescribed to treat?
Bute is prescribed for musculoskeletal pain and inflammation.
💊 What are the available formulations of bute?
Fortunately, bute is available as an oral tablet, paste and powder. And an intravenous formulation is available that must be administered carefully to avoid perivascular administration. Do NOT administer phenylbutazone intramuscularly due to the risk of clostridial myositis. Most commonly phenylbutazone as an oral formulation is dosed in grams. Bute IV is 200mg/mL. Bute has a 91% bioavailability when administered orally or IV. Dosage and frequency of administration may vary.
💊 What are the negative side effects of bute?
Bute has been shown to cause renal damage, gastrointestinal disease (stomach ulcers or right dorsal colitis), ulceration of the mouth and lowers total protein (TP). It should be avoided in neonates and minimized in pregnant mares.
💊 What is the history of firocoxib?
Firocoxib was first approved for small animal use in 2004. And in 2007, a paste and injectable formulation were approved for use in horses.
💊 What is firocoxib prescribed to treat?
Firocoxib is prescribed to treat pain or inflammation associated with osteoarthritis. It is a COX-2 inhibitor.
💊 What are the available formulations of firocoxib?
Firocoxib is commonly available as an oral tablet and liquid. It is administered once a day for up to 14 days. It is available as a 57mg tablet or 9mg/mL as a liquid. In some cases, a loading dose may be administered to increase serum levels of firocoxib. Firocoxib has a 70% bioavailability when administered orally.
💊 What are the negative side effects of firocoxib?
In general, firocoxib is more well tolerated than bute for some patients. Firocoxib has a decrease incidence of causing gastrointestinal disease; however, like with most NSAID’s firocoxib can cause right dorsal colitis. Other side effects include renal damage and sores/ulcers of the mouth, tongue and lips.
🩺 We always recommend following your veterinarian’s directions regarding the administration of an NSAID. Always discuss with your veterinarian before administering an NSAID to foals, young horses, pregnant or lactating mares. And to follow the medication’s label for storage recommendations.
