I know nothing about this subject, but my husband, a practicing veterinarian, says the line between a therapeutic and a fatal dose is a fine one.
No one else seems to agree with that. Correct me if wrong.
Have seen reports of taking much higher mg/kg without harmful effect.
Apparently some dog breeds are susceptible to toxic effects w/ high dosage.
“Certain types of dogs, including but not limited to collies and Australian shepherds, are also far more susceptible to the toxic effects of the drug”