Care for spider-bit Rabbit

Question
Hello,
I'm in the process of seperating my Netherland Dwarfs and Lionhead from the Theraphosa blondi, whose habitat they had been sharing, following advice I have recieved on this site.  During the move I heard one of my NDs, Achillies, let out a horrible scream. I ran in and saw blondi rearing up in a post-strike pose and Achillies was half-crouched down.  I am positive he had been bitten.  I called the vet and he is unfamiliar with rabbits and Theraphosa blondis.  Achillies spent some time on his side moaning, and is now limping and shaking.  He took some water and is eating (although not as much) but he is crying.  Can you help?

Answer
Dear Bill,

Okay, I'm not even going to ask why on earth you had rabbits sharing habitats with a tarantula--and a *Goliath* tarantula, at that. I fully realize that a question this bizarre and this indicative of absolute cluelessness about how to safely house rabbits could well be sent by a troll trying to get a rise out of me.  But for the moment, I will assume this is not a joke, and try to give you a serious answer.   

Tarantulas, like any spiders, are venomous.  The amount of venom injected varies on the size and state of agitation of the spider.  But any spider bite will be far more serious for a small rabbit than it would be for a human.  The venom of Theraphosa contains neurotoxins that work by paralyzing prey, and may also contain hemolytic toxins that digest tissues so that the spider can ingest prey the way a spider does.

I cannot believe you didn't get the rabbit to a vet *immediately*, or check the internet for rabbit-savvy vets when your own vet didn't know what to do, but you can find a good rabbit vet here:

www.rabbit.org/vets

I am sure that the best the vet can do at this point is to give Achilles supportive care including subcutaneous fluids, vitamin B injections to support the liver and organ function, and just wait and see.  If there is some remote chance that the vet has access to tarantula antivenin, this could help, but since it has probably been at least 24 hours since the bite by now, it may be too late for that.

Pain management is essential now.  It will be difficult to find a completely safe one, since an NSAID may interfere with coagulation (which is not a good thing if the bunny has hemolytic toxins circulating), nor opioids if neurotoxin reaction is a possibility.  Your vet will be able to best advise you.

I hope you can get Achilles some help immediately, and I am sure that if this whole thing is not a joke, that you will never get your rabbits anywhere near a giant tarantula again.  Good grief.

Dana