For ingested drinks, if you have time and the person is drinking alcohol, then you could use various date-rape drugs like rohypnol. Crush some benzodiazpines (valium, etc) into a wet martini and that would probably do the trick as well.
As far as injected is concerned, I was given a general when I had my wisdom teeth out. I counted back from 100 and only got as far as 97 before I was gone. Of course, you need a intravenous injection for it to work properly. I suppose you could just taser the target and then that would buy you some time to inject them.
There was that freaky stuff that Gerard Butler used in Law Abiding Citizen: it was a paralytic but apparently didn't affect the cardiovascular system.
Whether you think you can, or you think you can't, you are probably right.