A family member's dog's ACL surgery cost more than the ACL surgery they themselves got a few years before. Pet medicine is filled by pharmacies and costs as much as human medicine does. It's nuts.
What's supposed to be nuts about that? The surgery costs the same no matter whether you want me to do it to a dog or a person. The pills cost the same whether you want to feed them to a dog or a person. That's exactly what you'd expect.
Drug costs are mostly a function of development and marketing (there are exceptions where production dominates). Development cost is dominated by cost of human trials. It is not clear that drugs (particularly for non animals not destined for human consumption) should be as expensive as human drugs. And that is before getting to to unusual gap between US drug prices and international drug prices.
So what? Those costs happen before you sell the drug. That would make a difference for a drug that isn't approved in humans and therefore didn't pay the approval cost at all. It makes no difference for a drug that is approved in humans.
