Dani and her horse Polo
Phenylbutazone,
commonly referred to as “bute”, is a medication similar to aspirin that is
aimed primarily at horses, cows, and other large mammals for management of
pain. [1] It also helps reduce fever and inflammation. [1]
Originally designed for humans suffering from arthritis pain, it was found to
cause unpleasant side effects, such as vomiting and diarrhea. [1,2]
It may even have more potentially life-threatening consequences. There is a
great risk of increasing ulcers or bleeding in your stomach or intestines, it
can cause painful swelling from fluid backup in your limbs and lungs, and has
been related to a type of blood disorder. [3] The disorder, aplastic
anemia, is what happens when your body stops producing enough new blood cells,
and can result in full body failure if it is not caught and treated early
enough. [3]
If all of this happens, why use it?
It
is relatively non-toxic to horses, taking over 90 grams to be a lethal dose for
the average equine. [1] Consider this: Horses can weigh up to ten
times as much as we do! While the toxic effects can still occur, dosages are
generally going to be low enough and not frequent enough to cause damage. As
with any medication, using it on an as-needed basis is unlikely to result in
significant side effects.
So how does it work?
Similar
to aspirin, bute is a synthetic drug that works on blocking certain enzymes that
are responsible for smooth muscle cells to constrict or dilate, increase blood
clotting, and increasing spinal nerve activation of pain sensation. [2,4]
It is not selective to the two types of receptors, and does not bind
permanently like aspirin does. [1,2] It is gone from the system
typically in two to three days.
Cool, so how would I give it to my horse?
Bute
comes in either oral or IV form. [5] While IV is certainly fastest, only
someone trained in IV should give it. This is because it can cause death of the
tissue if it goes outside of the blood vessel. [3] Oral methods are
paste, tablets or powder. Find out which one your horse likes best (mine enjoys
the powder on a hot mash) and be sure to follow your vet’s instructions.
References
[1] Drug Bank. (2013). Phenylbutazone. Retrieved February 10, 2015, from http://www.drugbank.ca/drugs/DB00812
[2] Fraser, C. M. (1986). The Merck veterinary manual
(No. Edition 6). Merck & Co.
[3] Bishop, Y. M. (Ed.). (2005). The veterinary
formulary. Pharmaceutical press.
[4] Small Molecule Pathway Database. (n.d.). Phenylbutazone action
pathway. Retrieved February 17, 2015, from http://smpdb.ca/view/SMP00701?highlight[compounds][]=DB00812&highlight[proteins][]=DB00812
[5] Thal Equine, LLC. (2013). Bute & Banamine®: Commonly Used & Misused in Horses.
Retrieved February 21, 2015, from http://thalequine.com/bute-and-banamine-what-horse-owners-should-know/
