Placebo for sale?

Last night Levi woke up saying his knee hurt. He can be a little dramatic when it comes to pain and he thrashed around and moaned and couldn't go back to sleep. Schuyler rubbed his leg and tried to get him to relax, but he was having a lot of trouble going back to sleep. Then we gave him some Tylenol and he fell asleep within 2 minutes. Way sooner than the Tylenol could have begun to work. So I'm wondering, can you buy sugar pills? Some kind of safe placebo to give your kids? It seems like that would come in handy. I guess I should go find out if the internet knows.

Edit: okay after doing a bit of research on the subject I am forced to conclude that I am a terrible mother for considering it. I would be teaching my child that he should always take a pill for every minor ailment and also that he can't trust me to tell him the truth. Whoops.