I don't know if it's safe to keep him on Panacur continuously. hmm...
I've read that rabbits have fast metabolism, so most medication exits
their body pretty quickly. Maybe you can contact the HRS recommended
vets listed here:
http://www.ohare.org/vets.htm (perhaps you have
already :)
In addition to Panacur, I highly recommend growing fresh thyme for
your rabbit. It has an anthelmintic (vermicide) property, which "kills
a number of parasites including worms and protozoa found in the gut or
elsewhere, including some found in the liver, spinal and cranial
fluids." As a matter of fact, Sophie, one of our female buns, started
to recover from a very mild case of EC symptoms (nystagmus and light
swaying) as soon as she had some thyme and oregano (dried form - it
was the middle of winter at the time). She eats garlic stems and peels
voluntarily, too. Garlic is also anthelmintic. So are pumpkin seeds,
but I'm afraid they're too fatty for rabbits.
EC does affect kidney. Does your bunny drink a lot of water? That's
usually a sign of kidney problem. I know cinnamon is a kidney tonic
herb, but I don't know how effective/safe for rabbits. I used to have
a rabbit who liked to nibble on a cinnamon stick after I used it for
tea - she just liked the taste, imo.
FYI: Here's the Prozyme website (mutiple enzyme for pets). They're
still offering free sample.
http://www.prozymeproducts.com/
Hope your bunny has a long and happy life with you.
T.