The overdoses are being linked with a batch of heroin suspected to be laced with the painkiller fentanyl.
Fentanyl is an anesthetic that is 30 to 50 times more potent than heroin. It is used to treat patients with severe pain, but a variant called acetyl fentanyl is being produced by Mexican cartels and smuggled into the US for distribution, Matthew Barden, a US Drug Enforcement Administration spokesman, told Business Insider.
Fourteen different people were rushed into one Chicago-area hospital within a 24-hour period, many with needles still in their arm, according to the Tribune. Many of the overdose victims were stabilized with Narcan, a heroin antidote that reverses the effects of an overdose. At least one man is suspected to have died from overdosing.
"We suspect what is happening is the same thing that happened in 2006 when people were getting heroin that was cut with fentanyl, which is a very strong narcotic," Diane Hincks, a registered nurse and emergency-room director at Mount Sinai Hospital on Chicago's West Side, told the Tribune. "That's what we think is happening."
Barden told Business Insider that heroin addicts seek out heroin laced with fentanyl because it provides a more powerful high.
But the National Institute on Drug Abuse notes that cutting fentanyl with street-sold heroin amplifies its potency to life-threatening levels. Effects can include respiratory depression and arrest, unconsciousness, coma, and death.
"It takes very little for someone to overdose on it, to cause the level of respiratory depression that would cause you to die," DEA spokeswoman Barbara Carreno told Reuters.
In a period from late 2013 through 2014, federal officials estimate that there were at least 700 fentanyl-related deaths nationwide.
Over the weekend, Chicago police arrested two men on drug charges in connection to the outbreak of overdoses.