Ivermectin toxicity in mouse

Question
My fancy mouse was itching and causing sores on her skin from scratching so badly.  I did some reasearch and thought it might be a food allergy but changing her diet didn't  help.  So I took her back to the pet store from which I purchased her and the owner said she might have mites.  He said he'd treat her with "ivermectin" to get rid of them.  I didn't know to object.  He used a small syringe to squirt some drops on her and said see how she does in a week and change her bedding.  About 5hrs later she was neurologically impaired (stuporous movement, "hiccuping" like jerking movements .. not eating/drinking and def worse than just scratching!) so I brought her to a vet that said it was ivermectin tox and he gave her some SQ fluids and and an anti-inflammatory injection .. needless to say a lot of money later no improvement (it's been about 8hrs)  I've been giving her sugar water drops via a syring to try and keep her hydrated.  If you can offer and advice I would greatly appreciate it.  I'm not sure if once toxic if there is any chance of recovery ..  

Answer
Dear Donna,

How terrible! It's awful to watch a mouse (or other pet, or child, of course) suffer when there's nothing you can do.

I think the vet did what he could-- get the poison out of the system with fluids and give her something (perhaps a steroid?) to suppress any allergic reaction.  You are absolutely right to try to keep getting fluids inside of her.

If she likes to be held and it doesn't seem to distress her or cause her more pain, hold her. She will take strength and comfort from being in your hand and from you talking to her. Even if she is motionless, she will feel better. Other than that, a dark room, little noise, and some easy to eat and yummy food such as soft cheese or a cracker. Maybe she will lick butter off of your finger. Anything to make her feel better in some small way.  I'm sorry.

I wish I knew more about the ivermectin toxicity. Although I haven't used it myself and recommend a pyrethin spray to my clients, my breeder has switched to the spray and he says he even uses it on little babies. So the question is, did the pet store owner use an undiluted form or did she happen to be allergic to it? Did the vet give an opinion? I'd really appreciate you keeping me up to date because when the pyrethin doesn't work I do want to recommend the ivermectin.

Best of luck to her,

squeaks,

Natasha