You should also get some of this to throw in their house and run. A few of ours became sick (lethargic, glassy eyes and also sneezing a lot) because they had mites from an old hen house we put them in so our neighbor can watch them when we went away on holiday. This cleared them up in a few days in addition to the VetRX we gave them as mentioned above.
Food Grade Diatomaceous Earth
https://www.amazon.com/dp/B00JJ71LW6/ref=cm_sw_r_sms_c_api_Kj.sAbSWGH9MX
As a preventative care, food grade diatomaceous earth is supposed to prevent fleas and other bugs. After cleaning bunny litter box I sprinkle it in the box then put fresh litter on it. I use this brand from Amazon.
http://www.fleabites.net/kill-fleas-with-diatomaceous-earth-powder/