I dunno about drugs but I heard that Chamomile Tea helps. I know from experience that it does, I was overly-hyper one night and took it without realizing what the effects were and about a half an hour later I was out. Plus it's natural and has other health benefits as well

http://www.homeremediesweb.com/chamo...h_benefits.php
http://www.buzzle.com/articles/chamo...-benefits.html
http://www.solveyourproblem.com/slee...hamomile.shtml