I would say that if he is a helthy bunny with a proper diet (hay, water and nothing else like fruits) then he "should" be okay. I would just call the local vet and ask them about it.
It's not that easy to actually poison Rabbits however due to some "hidden" problems a Rabbit can have (that you are not aware of) can cause complications.
Then again if there are no "vet options" since its weekend: monitor him: how are the poops (refresh the litterbox), monitor eating habbit and monitor how active he is.
Keep us posted!