Ivermectin is fine. Here's a site with safe anti-worm meds and dosing info:
Panacur is Fenbendazole
Some rabbit breeders do routinely worm their herds because they have less control over what they are exposed to, since the rabbits might be in a barn or shed that's more "outside" than "inside", and they have rabbits coming and going so often. Panacur or Ivermectin are typically used.
If you are going to use these, though, get a paste form that is made for goats, sheep, horses, etc.