Phenylbutazone

Phenylbutazone is used as a non-steroidal anti-inflammatory drug (NSAID) for the treatment of chronic pain, including the symptoms of arthritis. Its use is limited by such severe side effects as suppression of white blood cell production and aplastic anemia.

Side effects and disadvantages of phenylbutazone

Side effects of phenylbutazone are similar to that of other NSAIDs. Overdose or prolonged use can cause gastrointestinal ulcers, blood dyscrasia, kidney damage, oral lesions, and internal hemorrhage, especially pronounced in young, ill, or stressed horses. Effects of gastrointestinal damage include edema of the legs and belly secondary to leakage of blood proteins into the intestines, resulting in decreased appetite, excessive thirst, weight loss, weakness, and in advanced stages, kidney failure and death.

Phenylbutazone should not be used in combination with blood thinners (e.g., Coumadin), as it amplifies the anticoagulant effects of these drugs; with other NSAIDs (all NSAIDs are additive); or in horses with known kidney or liver problems.

Periodic blood tests are recommended when using phenylbutazone as Agranulocytosis can occur. Periodically testing the blood may catch this issue before it is too late.

Phenylbutazone should be used cautiously in pregnant or nursing mares, as it may be toxic to the embryo and can be transferred via the umbilical cord and by milk.

High doses of phenylbutazone may be considered a rules violation under some equestrian organizations, as the drug may remain in the bloodstream four to five days after administration.

In humans, Phenylbutazone is very dangerous, as it can cause aplastic anemia. The medicine should be given in a paste form to avoid contact with the medicine. Never breathe powder from crushing tablets.