Phenylbutazone can have some nasty side effects — we all know that. However, it is also an inexpensive, highly effective and long-lasting anti-inflammatory, analgesic and antipyretic (fever fighter), which is why veterinarians tend to favor it for many short-term and even some long-term problems.
When it becomes clear that bute is the best choice for your horse, we have some sensible guidelines that can help decrease the chances of side effects:
• Avoid use in very old or very young horses, or horses with kidney disease or ulcer disease.
• Avoid use in horses with a history of adverse reaction (e.g. going off feed, abdominal discomfort) after short courses of phenylbutazone.
• Avoid long-term use in favor of other methods for control of pain and inflammation (hydrotherapy, joint nutraceuticals, some herbal remedies, etc.).
• When using phenylbutazone, always give it with grain but avoid hay for an hour before and an hour after (hay binds phenylbutazone and delays absorption of the drug).
• Use effective doses but not excessive (up to 2.5 grams for an 1,100-pound horse).
• For acute conditions or flare-ups of old conditions where bute is indicated, treat with a rapidly tapering dosage schedule, e.g.:
1st dose – 2 to 2.5 grams;
2nd dose – another 2 to 2.5 grams in 24 hours;
3rd dose – 2 grams 36 hours after second dose;
4th dose – 1.5 grams 36 hours after third dose (only if needed).
Three doses of phenylbutazone should be adequate to get control of pain, heat and inflammation for most conditions. If severe signs persist at this point, you either need to add more intensive local therapy (cooling, etc.) — which should have been done in the first place instead of relying solely on bute — and consult your veterinarian to be certain there is no infection or an underlying condition that was missed or became more obvious since the problem first developed.
Used properly, phenylbutazone is still an extremely valuable drug. The trick is to use it intelligently, only when absolutely needed and only for as long as absolutely needed (this is actually good advice for use of any drug).
NOTE: Research in laboratory animals has shown that high doses of MSM can protect against ulcers induced by NSAIDs like phenylbutazone. This has not been investigated in horses, however, so we cannot say for certain that it will have the same effect. However, MSM has proven to have a multitude of good uses and is worth a try. The dose would likely be about 30 to 40 grams of MSM given 30 minutes before the phenylbutazone.