Beneficial effects of furosemide

[TGJB]

Briefly, because in some cases your answers actually made this more confusing--

You know (I have to assume) that virtually all horses race on Lasix, and that only a very small percentage have actually been observed to have bled before having been put on it, even in states where that is supposed to be a pre-requisite.

And it doesn\'t have to be 15 compared to 20 pounds, it could be 5 compared to 15 if you use the lower does first (aside from other variables). And I do know of horses that were given smaller doses, bled through them, then were given a higher one next time, with no intention to cheat. One Graph Racing filly in particular. She shouldn\'t have gotten the lower dose to begin with.

On your last point, I have said that to trainers and owners many times. Bleeding is as likely to be an effect of a problem as a cause.

[sighthound]

>> You know (I have to assume) that virtually all horses race on Lasix, and that only a very small percentage have actually been observed to have bled before having been put on it, even in states where that is supposed to be a pre-requisite.

Yes, but over 85% of horses are thought to be bleeders (much previous work on this in the literature).  Nearly all are not visible on endoscopy post-race.  In other words, horses can bleed a bit, but scope clean post-race.

Read the study - it was done on South African horses that never get lasix to race.

>> And it doesn\'t have to be 15 compared to 20 pounds, it could be 5 compared to 15 if you use the lower does first (aside from other variables).

The body weight of the horse isn\'t exactly like the weight the horse carries on it\'s back.  A pound of body weight is not like a pound of jockey or a pound of lead.

Seriously - the tradeoff in electrolytes lost, and simple body water lost, and the metabolic effects of that, is far more signficant than worrying the horse is racing 15 pounds lighter than normal.  

And the water loss each horse has, for each time it\'s given lasix, is not predictable in the least, as it\'s based upon the horses\' current hydration status, it\'s electrolyte status, when and what it has been eating, and quite markedly by the environmental temperature and humidity.

>> And I do know of horses that were given smaller doses, bled through them, then were given a higher one next time, with no intention to cheat.

Yes, that\'s not rare.  Due to the other side effects mentioned, some trainers want to try a smaller dose.