Pharmacokinetic studies are limited in reptiles however they are done. Veterinarian's use drug formulary's to decide on drugs to use. A vet may see 10 or so mammilian species, but there are thousands of reptile species readily available. Dosages and other medical information pertaining to the drug, it's metabolism, and excretion are often extrapolated from studies done in other reptilian species, and secondarily, in mammalian species. Your veterinarian will have considered your questions, as they are necessary for any and all prescriptions (yet another reason why I am so hard on people insisting on finding Baytril doses over the net cuz they can get it at whatever hick website). The information and experience available to your veterinarian will influence any decision which is arguement to looking for the most experienced herp vet in your area. In general I would say that no, long term effects are not a serious threat. With that said however, if used improperly there is definately a threat. Why is the lifespan reduced? Generally because alot of organ tissue cannot be regenerated like skin or muscle can. Therefore if say, amakacin is used in a dehydrated animal, kidney damage may result that the animal will have to live with for the rest of it's life. When old age finally starts to take a toll on the kidney, there is that much less healthy tissue to start out with.
I hope this gives you what you are looking for. I avoid giving exact data on doses or reptile drug formularies, but if you would like to get more detail, ask your veterinarian if you may browse through his guide.
