A new and dangerous form of heroin is killing dozens of people across the Eastern U.S. Dubbed “killer heroin,” the drug is spiked with fentanyl, a powerful synthetic opiate used to treat people with chronic pain, including cancer patients.

According to Tech Times, fentanyl is 80 times more potent than morphine and is lethal if taken in overdose. Heroin users are often unaware that the drug they’re taking contains fentanyl.

"A very small amount can exert a very significant effect," Eric Strain, director of the Center for Substance Abuse Treatment and Research at Johns Hopkins University, told the Associated Press.

In recent weeks, fentanyl-laced heroin has killed more than 80 people across the country. WCNC reports that in Maryland, at least 37 people died from the super drug, and in western Pennsylvania, 22 people perished from the “killer heroin.” In Rhode Island, heroin containing fentanyl has killed 25 people. Other states reporting deaths from fentanyl include Vermont and New Jersey.

More recently, dealers have added fentanyl to augment bags of heroin, marketing the resulting cocktail to their customers as an improved high.

"The dealers push this as being a super high, which it is, but it's also lethal," Ellen Unterwald, director of the Center for Substance Abuse Research at the Temple University School of Medicine, told the Associated Press.

Authorities have identified heroin bags containing the labels “Bud Light,” “Theraflu” and “Income Tax” as containing fentanyl.

According to the National Institute of Drug Abuse, fentanyl, like other opiates, boosts dopamine levels in the brain, producing a state of euphoria and relaxation. Mixing fentanyl with heroin amplifies the potency of both and produces drowsiness, nausea, confusion, sedation and, in more extreme instances, unconsciousness and respiratory depression. It only takes a small amount of fentanyl to stop a person’s breathing.

"It's a different heroin now," T.J. Smith, a spokesman for the police in Anne Arundel County, Md., told the Associated Press. "You can't use that same amount of heroin that you used a year ago because now it has a fentanyl kick in it."

Authorities say drug addicts are increasingly turning to heroin because of federal crackdowns on prescription drug abuse.

Still, fentanyl-laced heroin is nothing new. As Slate noted, the drug combination has been on the streets since the 1970s, and fentanyl overdoses kill dozens of people every year.

The most significant spate of fentanyl-related deaths occurred in 2005 and 2006. During that time, nearly 1,000 people died from fentanyl across the U.S. Authorities were able to trace the source of the street fentanyl to a single factory in Toluca, Mexico.

After Philip Seymour Hoffman was found dead in his Manhattan apartment from an apparent heroin overdose earlier this month, authorities suspected the drugs he took contained fentanyl. However, an investigation discovered that the heroin used by the acclaimed actor did not contain the additive.