I was prescribed bute in high school ( mid1970’s), in order to run hurdles on hot shin splints. By a doctor. It was very effective, and I experienced no negative side effects. It was encapsulated with a coating, looked like red smarties.
At racetracks, death from ingesting butazone meant for horses has been a known occurrence. Usually uneducated backstretch workers, who are injured and sore and don’t know any better. Liver and kidney problems I think is what kills them. Dosage too high, and not encapsulated, and kept on for a long period of time. Regular handling of bute being used for horses isn’t a health danger. It’s not like Rompun. Rompun WILL kill you if injected accidently into a human. Even handling a syringe that has some on the outside of the plastic, or pulling a needle cap off with your teeth can cause a reaction. A vet once told me that if you accidently stab yourself with a needle with rompun in it, you are to grab the bottle, so that when (IF) you get to hospital in time, they will know what drug you have in you, so that they can give you an antidote, and treat you effectively. Because by the time you get to hospital, you will be non responsive, with the bottle clasped in your fist.