|Medication Committee Corner: The Missing Florida Bute Study|
The Horsemen''''s Journal - Winter 2010
By Kent H. Stirling, National HBPA Medication Committee Chairman
In early September of this year, Dr. Larry Soma of the University of Pennsylvania sent his equine medication advice to the Pennsylvania Horse Racing Commission and the Pennsylvania horsemen in a 16-page document titled, “Summary of Medication Recommendations.” On page 12 of Dr. Soma’s
document, he began a review on phenylbutazone, commonly known as bute. On page 13, he displayed a chart and explanation of what would happen if horses were administered 2.0 grams orally (pills) of bute daily for four days, followed by a 2.0 gram IV administration of bute on the fifth day, which would be given 24-hours before serum samples were collected. The average plasma concentrations in the six horses studied were 1.6 mcg./ml., with a range of 0.9 to 2.6 mcg./ml. From this, we can conclude that at LEAST one, and possibly two, horses out of the six were higher than the 2.0 mcg./ml. threshold recently adopted by the Racing Medication and Testing Consortium (RMTC) and the Association of Racing Commissioners International (ARCI).
On page 15 of his document, Dr. Soma demonstrated by text and graph what would happen if 20 horses that had NO, repeat NO, bute in their system, from bute pills or otherwise, were administered a SINGLE 2.0 gram dose of bute intravenously. Again, this group of now 20 horses had no prior
administration of bute. The 24-hour mean post-administration plasma concentration was 1.2 mcg./ml., but the range was 0.5 to 2.1 mcg./ml. At LEAST one horse was over the 2.0 mcg./ml. threshold despite no previous bute in the horse’s system, and this was after just one IV dose of bute.
Wrote Dr. Soma, “These data indicate that even with no prior administration of PBZ (bute), a dose of 2.0 grams 24 hours prior to post-time may produce a violation of the 2.0 mcg./ml. threshold.”
Below this disturbing quote was this footnote: Phenylbutazone IV administration to 20 horses (courtesy of the Drs. Sams and Callahan of the University of Florida).
Did Dr. Soma analyze bute simply from the Florida study, or had this data also already been analyzed by the University of Florida? Did Dr. Soma somehow let the cat out of the bag while he was attempting to warn his commission and horsemen of potential problems with the 2.0 mcg./ml. bute
threshold? Over two months later, why has no one seen the results from the University of Florida study? Didn’t the University of Florida ever finish analyzing and/or report its own study results?
I mentioned this research, and the conclusion of Dr. Soma, at a hearing in Tallahassee when the State of Florida was attempting to adopt the 2.0 mcg./ml. threshold for bute (it was not adopted). Dr. Callahan (I think it’s Colahan) of the University of Florida was present, as were several RMTC board members. None denied what I presented, and none seemed surprised by it. In fact, a veterinarian present stated that she had heard the 2.1 threshold overage was really only 2.05 mcg./ml. Again, I mentioned these results at the October meeting of the RMTC Board of Directors, and no one seemed surprised by it.
So what is going on here? Did The Jockey Club, ARCI, and others find that the research just didn’t back up the 2.0 mcg./ml. threshold on bute that was seemingly pulled out of thin air?
Certainly the RMTC board was not aware of this study when it voted to lower the bute level, because it had not been completed then. But what about the ARCI board that voted in late October to lower the bute threshold? Were they aware that 2.0 mcg./ml. threshold meant an automatic, significant increase in bute overage positives?
So just where is the missing Florida bute study, and why is it still missing?