Opiates and related narcotics (See 14.5.4.3)

http://pulmccm.org/main/2012/critical-care-review/managing-opioid-overdose-in-the-icu-review-nejm/ Probably should read the original article (links on the page) if you want a more thorough review

http://lifeinthefastlane.com/ccc/opioid-overdose/ Very basic review