Everyone is probably sick of reading my opinion, but here goes:
Most drugs have side effects, even at recommended dosage levels.
Exact dosing for an animal with such a small body size can be very difficult, especially if you are administering a wormer by dusting flies (that is in no way an exact method of dosing if you think about it).
I have heard of multiple breeders with deaths that occurred after preventatively dosing frogs with Panacure.
Because I have a conservative bent on medicating (a personal preference), I do not like the idea of preventatively administering a wormer, as you are exposing your animal to the side effects inherent in the particular drug you are administering without knowing if animal truly needs it.
To my mind, a better approach is to pay the extra $10-$20 to have a decent vet look at a fecal before treating; that way the appropriate medication can be administered if necessary, and I don't have to take the risk of medicating a valued (and often times expensive) pet if the fecals come out negative.
Plus, simply dosing a frog with medication may not take care of the problem if you keep the frog in the same environment after treating, and you may not be administering a drug that is effective on a parasite infecting the animal.
I'm not saying preventative treatment is irresponsible or bad, but I do think that hobbyists should know that there are risks associated with it, and relatively simple ways to mitigate those risks.
I think it would be great to hear opposing opinions and experiences other froggers have had with preventatively worming frogs, as I think we could all learn from such a discussion if approached delicately. I think that the farmed pumilio from Seaside were preventatively dosed and most are doing okay, but I really don't know the particulars.
DISCLAIMER--none of the above was intended to be veterinary advice, just a viewpoint with some observations.
