With any ill iguana I always advise to find the flower nasturtium also.
it is a natural antibiotic and is good and safe to iguanas.
It is a good avenue to go down if its not possible to see a vet straight away.
However I am speaking about the species
iguana iguana (The green iguana) so I can only say that. The over view would be similar to most reptilian species that there is a better immune system at higher temperatures.
I have read kaplans work at great dissapointment, all I will say is her work does more than good but do not take everything she says as gospel.

x
and good luck at the vets ems, let us know how you get on xx