system
Given the following post, respond as if you're commenting on Reddit:
human
Is there a chemical you can spontaneously inject into the muscle tissue and have someone immediately pass out like Hollywood shows?

I thought for an intravenous injection to work/have rapid onset it had to be... intravenous?
gpt
There are medications that can be used for 'rapid tranquilisation'. These can be given IM and, as the term suggests, can cause tranquilisation. Examples are lorazepam, haloperidol and promethazine. Their effect isn't immediate, it can take minutes.