system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why are we able to "painlessly" put down our pets with drugs, but often botch lethal injections?

Why does this happen?  Couldn't we just do some math and give the human a higher dose based on BMI and height?  What's the difference between the drugs; do we even use different drugs for dogs and humans?
gpt
Short and Simple: Nobody manufactures the drugs for lethal injection in humans, so we wind up using *really old* drugs or a cocktail of things not meant for the purpose of killing humans. Also, there aren't many doctors willing to administer lethal-injections... and improper application can leave someone alive and in agony instead of dead.

Longer and Detailed: The Pharmaceutical Companies that make the drugs for Lethal Injections *know* how radioactive the topic of Capital Punishment is. Anyone associated with it is poisoned. Social Media will *crucify* anyone who sells the drugs used to kill people... and that will result in lost business across **all** of their products.

There aren't many executions in the United States, even when the needed supplies are available. That means that lethal injection drugs are a *really* niche product. The lost profit from *not* selling the drugs for Lethal Injection is **much** less than the lost profit from losing sales in every other sector.

So... that opens up another question: Why isn't there a company that *just* fills the need for lethal injection drugs? 

The answer to that is that you can't make a profit in that market alone. It's a ludicrously small market, needing less than a thousand dosages of your product per year. Since you can't sustain a company *on* lethal injections, and any company that could afford to do it as a side-gig won't touch it with a ten-foot-pole, there's no supplier.

Which brings us to what we use: Old drugs from when companies *would* sell them, a finite supply that grows less effective with time; and trying to mix a cocktail of drugs that will do the job... to sometimes horrific results.

Doctors and Nurses to administer the lethal injection are hard to find for the same reason. The entire concept of Capital Punishment is **radioactive**. Even if the state shields you from being fired from a hospital or losing your license to practice medicine, your patients **will** eventually learn what you did... and a lot of them are going to look for a doctor that doesn't kill people. Losing your patients isn't worth whatever the state pays you to kill someone.