The overdose-reversal drug Narcan is displayed during training for employees of the Public Health Management Corporation (PHMC), Dec. 4, 2018, in Philadelphia. (AP Photo/Matt Rourke, File)

The U.S. Food and Drug Administration on Wednesday approved selling the leading version of naloxone without a prescription, setting the overdose-reversing drug on course to become the first opioid treatment drug to be sold over the counter.

Naloxone reverses an opioid overdose if administered in time. (WTTW News)

The key culprit appears to be the widespread availability of the powerful synthetic opioid fentanyl.

Why is Puerto Rico sending addicts from the island to Chicago? WBEZ reporter Odette Yousef explains the story.

U.S. Sen. Mark Kirk expands efforts to fight heroin overdoses in Cook and surrounding counties.