Opioid overdose is an acute condition due to excessive opioids. Examples of opioids are: morphine, heroin, tramadol, oxycodone, and methadone. It differs from opioid dependency. Although opioid overdose does not constitute a majority of the overdoses seen in the emergency department it is important to rule out in people given its potential for mortality and the ease of reversal. Dependence on prescription opioids can stem from treatment of chronic pain and in recent years is the cause of the increased number of opioid overdoses.