can another course of baycox be given?

Question
hi....i had the upset of adopting two rescue french lops who were fine and healthy..except one had small organs when she was spayed.
Within two weeks she was pts and it was respiratory failure after a high fever and the necropsy showed extensive ocytes of hepatic coccidia in her liver and bile duct.
So we needed to treat her surviving sister and our two male buns for coccidia.
some vets say a course of septrin..others baycox. Two exotic vets recommended the lower dose as it causes appetite loss.

All 3 bunnies had two days of baycox..then a two week break...then another two days of baycox..and then this week..a fecal float test.
Both my boys are clear..only one of them is bonded to the girlie bun.
However poor bluebell has tested positive for pinworm....shes due for another course of preventative panacur anyway so thats taken care of. However my vet is having great trouble getting the advice needed.
A phone call from a bunny vet at bristol university in the only bunny only clinic in britain..is in the pipeline.
Have you had any luck with repeating the baycox dose as it is or have you used the higher dose?
how many times can it be repeated to kill off the hepatic coccidia?
I forgot to mention that my buns are free range house buns..the boys are over 5yrs old......but bluebell is now only 10 months old..and her sister was pts in november.
Any tips would be greatly appreciated. Your article on gi stasis has helped save so many bunnies lives..

Answer
Dear Debbie,

We use a slightly different formulation of toltrazuril sulfate, Marquis, to treat coccidia.  It's formulated for horses, but is the same drug.  I just don't know if the carriers are different, or if that makes a difference.  So take what I say here with a small grain of sodium chloride:

We have used Marquis (a.k.a. ponazuril, a.k.a. toltrazuril sulfate) on rabbits and hares at doses ranging from 20mg/kg to 50mg/kg once per day, and have gone as long with treatment for up to 30 days in a row.  We have often repeated the dosing regimen (our wild sanctuary hares live outdoors, where they can constantly be reinfected), and have seen absolutely no adverse side effects.

I hope your little girl can be treated successfully for the hepatic coccidia.  Maybe ask the vet about dosing her for three days with the higher dose, then backing off.  When you're dealing with pathogens or parasites, it's best to hit them as hard as you possibly can without harming the host.  This gives less chance of selecting for resistance.

I hope you have success with this.  Good luck!

Dana