"1)are these the same thing?"
Yes. Panacur is the brand name for fenbendazole, just like how Aspirin is the brand name for acetylsalicylic acid.
"2)is the pancur used on dogs the same as the powder form used on herps such as dartfrogs?"
Essentially, yes. It's the same drug, but it might be a different concentration. Fenbendazole is available as both a liquid, a paste, and a powder that you have to reconstitute yourself, but they're the same drug. The paste that's used for farm animals is MUCH more concentrated than the form used for dogs, cats or even herps.
"3)some people dust their food items weekly with fenbendazole the same way they dust with vitamin and calcium powder. Are you able to overdose the herp dusting like that?"
This is very dangerous. Fenbendazole is a prescription drug (and even though you can buy it over-the-counter from farm animal supply companies, this is technically illegal, but many farmers don't want to have to pay a vet to deworm their animals, so they get away with it), and like any drug it has potentially harmful side effects. There are two problems with this method of "deworming:"
a. You do not know how much of the drug the animal is ingesting. Dust can fall off of crickets, and you cannot measure the exact amount of powder that's left on the feeders. Like any drug, fenbendazole has a minimum dosage required or it won't work at all, and a maximum dosage because too much will drastically increase the risk of harmful side effects occuring. If you're underdosing, you could just be creating fenbendazole-resistant parasites!
b. This kind of long-term treatment is bad for the animal! Fenbendazole is metabolized by the liver, and giving the animal's liver this extra work on a weekly basis is definitely not good (especially if you may be giving a higher-than-safe dose). Most vets and vet techs agree that every herp should be tested for parasites every 6-12 months to see if drug therapy is needed.
"4) is the weekly powder dusting's alone strong enough to rid a heavy load of parasites? Or are liquid dewormers still required afterward to finish off the job?"
Fenbendazole is effective at a dose of 50-100 mg/kg PO once, repeated in 2 weeks for reptiles, and either 10 mg/kg PO once or 50-100 mg/kg PO once for amphibians (depending on the reference). You must consult with your vet before starting any drug therapy. These doses are ranges because individual animals may require an adjustment to the treatment according to their health status and history. Giving a drug without having a general physical exam (at the very minimum- blood work along with it would be optimal!) is irresponsable- even experienced keepers can miss something about their herp's health, and a vet needs to decide what dosage is needed.
It should also be mentioned that fenbendazole only kills nematodes (roundworms). Cestodes (tapeworms) and trematodes (flukes) can also infect herps, as well as protozoa (single-celled parasites) such as coccidia, Cryptosporidum, flagellates and amoebae. A different drug is needed to treat each one! So you need to have a fecal exam done at the vet's, anyways, to see if fenbendazole will actually kill what parasites your herp has!
Christina Miller
Herptiles.net