Sounds like you did the right thing. Imagine giving someone medication w/o any med history and them suffering adverse effects? Not just from a liability standpoint, but how would you feel as a person?
Me, I carry 10mg Valium (diazepam) for long flights to make me real happy if the Ambien don't knock me out. Never had it injected, it must be nice to get that "I don't care" feeling real fast...