system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:: Why don't we use Morphine for lethal injection?

There have been a lot of botched lethal injections in the past, and the chemicals used are very difficult to acquire. Why don't we use morphine or cyanide to kill someone? We know they will die, and the chemicals are much easier to get a hold of.
gpt
There are many pharmaceutical companies that explicitly state "If you want to buy our drug, you have to promise not to use it to kill people."  This is the reason that the US has had so many issues with lethal injection drugs recently; some cocktails have been disallowed by the manufacturers, and some of the new mixtures haven't been as thoroughly tested and aren't having the expected results.

This is a guess, but I'd say the morphine manufacturing companies slapa sticker on the bottle that says "No executions, thanks!"