I took 2 years vet tech. I was amazed at how basically everything was almost the same doses for animals and humans. Mg/kg.
As my instructor pointed out, evolutionary wise we are only 2% different from most animals. Why shouldn't our meds work on them and theirs on us?
That's why animal testing works.
You start further away in the cheapest test subject range then work your way upto primates, or in covid cases, liberals.