Sulfa based medications have shown to be nephro-toxic in Drymarchon spp., though such have been used safely when administered correctly and to specimens that have been well hydrated.
As was mentioned earlier, hydration should be a great concern to the Dry keeper, as Drys are very sensitive to the effects of dehydration, which can cause both acute and chronic renal anomalies.
I am no advocate of "shot-gunning" any animal with a medication, as doing so generally creates greater problems later on. Prior to administering any medication you should know what the indications and contra-indications of the med/s are, what you are treating for and the correct dosing applications. All of this information can be provided by a veterinarian, preferably one well versed in the medical care of herpetofauna, which in most instances is required by law, as prescribing prescription medications and diagnosing injury and illness is considered practicing medicine, which requires a license...
Best regards,
Jeff
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Jeff Snodgres
University of Arkansas
snodgresjeffreys@uams.edu
501.603.1947