Grayson Study Shows Earlier Lasix Administration Effective

The results of a project funded by Grayson-Jockey Club Research Foundation that examined furosemide administration at 24 hours prior to a race, indicated that Lasix is capable of attenuating exercise-induced pulmonary hemorrhage (EIPH) for a longer duration than traditionally believed. The results of the study were published in the Journal of Veterinarian Internal Medicine.

The study examined fit Thoroughbreds who were known bleeders and started in the clinic on the treadmill with all horses receiving one of seven different treatments, with the 250 mg dose representing the traditional low dose allowed by regulatory authorities and the 500 mg representing the traditional high dose:

1. Placebo (saline)
2. Conventional (low-dose, 250mg, 5ml) furosemide four hours pre-exercise
3. Controlled water access only with no medication (maintenance water access for 24 hours pre-exercise)
4. Low-dose furosemide (250mg, 5ml) 24 hours pre-exercise with free access to water
5. High-dose furosemide (500mg, 10ml) 24 hours pre-exercise with free access to water
6. Low-dose furosemide (250mg, 5ml) 24 hours pre-exercise with maintenance water access
7. High-dose furosemide (500mg, 10ml) 24 hours pre-exercise with maintenance water access

According to a Monday release from Grayson, from all seven of these treatments, the one that was clinically relevant and showed the least amount of blood from horses that suffer from EIPH was treatment No. 6, low-dose furosemide given at 24 hours pre-exercisewith maintenance water.

After the clinical trial, the horses returned to the racetrack, trained for one month, and then ran in two simulated 1,100-meter (slightly longer than 5 furlongs) races. The horses received treatment No. 6, the most effective treatment as defined by clinic trial in one race, and a saline control in the other. The races were separated by two weeks of training.

“Results from the simulated races show that, for horses that are known bleeders, the low-dose furosemide administered at 24 hours prior to post with maintenance water has great promise as a replacement to the current four-hour administration of furosemide,” the Grayson release said.

To view results of the study, click here ncbi.nlm.nih.gov/pubmed/31397944