NSAID toxicity

Veterinary advice should be sought before applying any treatment or vaccine.

NSAID Toxicity

Nonsteroidal antiinflammatory drugs (NSAIDs) are a diverse group of anti-inflammatory, antipyretic, and analgesic drugs that are often used as part of supportive therapy in horses for a wide range of conditions. There are many different types of NSAIDs, which include:
  • Salicylates: Aspirin
  • Propionic acids: Ibuprofen, ketoprofen, fenoprofen and naproxen
  • Pyrazolones: Phenylbutazone (also known as "bute")
  • Panthranilic acids: Meclofenamic acid
  • Aminonicotinic acids: Flunixin meglumine (Banamine)
Although all NSAIDs are potentially toxic to horses, some drugs are more toxic than others. For example, horses are more at risk of NSAID toxicity from receiving phenylbutazone than flunixin meglumine, which is more toxic than ketoprofen. NSAID toxicity results in two well-recognized syndromes in affected horses, which include:
  • Gastric ulcers
  • Right dorsal ulcerative colitis (RDUC)


Loss of appetite
Colic signs
Poor body condition


  • History - recently receiving NSAIDs
  • Clinical signs
  • Physical exam
  • Laboratory tests



Supportive care


  • Only provide horses with NSAIDs under the direction of your veterinarian and only in the doses/time intervals recommended
  • Never administering phenylbutazone and flunixin meglumine to horses' concurrently

Scientific Research

General Overviews

Risk Factors

  • Dehydrated horses
  • Stress
  • Concurrently administering phenylbutazone and flunixin meglumine
  • History of previous reaction to NSAIDs
  • Concurrently administering nephrotoxic drug therapy, such as aminoglycosides
  • Horses with existing renal or hepatic disease