You are aware that "pharmaceutical" vs "poison" is a matter of doses and control, right?

That a dose not too different from adult posology of paracetamol can be lethal?

Maybe you did not know that "heroin" was developed at Bayer (the informal name came out of the trials after the reports from the testers)...

Pharmacology is the discipline that deals with drugs.

I don't know about kids, but yes it is used in general anesthesia.

yes. They used it for a heart surgery on a new born that I know.