In the region where I live (north east of Italy), local agricoltur authorities have declared that Apistan (R) is ineffective, because of the large diffusion of Apistan-resistant Varroa and its use has been stopped. To the beekeepers associated in the syndicate (almost the totality of the active beekeepers) they distribute Api-Life-Var (R) a mixture of  thymol, eucalyptol, menthol, adsorbed to a solid substrate, to put in the hives for a month before winter.
It is not so effective: a second treatment with Perizin (coumaphos) is reccomended and always necessary. I'd like to try mineral oil instead of this drug: I am wondering if such a treatment would be reasonable, or adverse effects are to be expected.