I get Eradimite from my vet. It works wonderfully for my guys. I'm pretty sure that it's not a prescription item though.
http://underbid.com/action/display/i...sku/ERADI.html
And there are other ear mite treatments that you can get at pet stores that will probably work. I just really like this one, as it doesn't tend to dry out the ears like some of the pet store kinds can. Then you have the little ones scratching like crazy for a few days at their ears...and we all know that's not fun.