Endurance.Net Ridecamp Archives

As you may guess by the subject, I have a rather sick horse.  He is on the mend, thank goodness.  Short version, I noticed he seemed listless and lethargic.  He was EDPP, but he tired easily and took longer than usual to recover from activity.  I called the vet out (the irony at this point is, after he was looked at, everybody at the ranch was telling me how they saw my horse laying down a lot -- that would've been nice to know sooner, folks....), who couldn't find anything obviously wrong.  So, we drew a blood panel.  A few days later, vet called and said the horse was anemic, and hypothyroid.  So, he's on a high-iron supplement (red cell) and thyroid medication.  Now my questions is this:  does anybody know if levothyroxin (the thyroid med he's on) will disqualify him from endurance?  If I have to take him off of it to compete, how long do I withdraw it before a ride?  If he ends up taking this for life, and he'd have
 to go off it to compete, I will very likely retire him from the sport.  Sad, really, since he loves it.