http://www.anapsid.org/resources/rxdose.html
heres a site with common meds.. ivermec is not recommended in reptiles.
heres a quote from the above on the side effects.
Ivermectin is administered in near-toxic doses to be effective, and must be repeated often 3 times to be as effective as the far less toxic fenbendazole. Merck, the maker of ivermectin, does not recommend its use in reptiles. Often fatal or nearly so to small, debilitated reptiles. May cause paralysis, blindness, etc. in larger reptiles. Its use is not recommended for lizards and snakes; it is nearly always fatal when used in turtles and tortoises. Ivermectin toxicity includes paralysis and blindness
I have seen this do some damage with dragons. I usually recommend against treating with this drug due to all the bad info out there. I would make sure to keep that snake hydrated. look for any type of odd behavior or side effects.
and it would be best to find a herp vet around you. Have you tried looking?