HOLYOKE, MASS. (WHDH) - Police in Massachusetts are warning the public of a new drug cocktail that is on the streets and known to cause “violent, bizarre, and self-destructive” behavior, officials announced this week.

Emergency crews responding to an uptick in overdoses in Holyoke in recent days have come across heroin bags adulterated with many substances, including fentanyl, caffeine, and MDMB-4en-PINACA, according to the Holyoke Police Department.

Police described MDMB-4en-PINACA as a “synthetic cannabinoid.”

“Our first responders, police, fire and ambulance crews are observing behavior consistent with PCP ingestion in some of the overdose patients we are responding to,” the department said in a statement.

In some cases, police say patients are violent and showing symptoms not generally related to heroin use.

“It is confusing and difficult to treat at the scene and dangerous for first responders,” the department said.

Some patients have exhibited bizarre, self-destructive physical behaviors, such as attempting to jump from high places and fleeing into busy traffic patterns, officials said.

Ambulance crews have reported “extremely high blood pressures” and “dangerous heart rates,” among other respiratory issues.

Officials say Narcan may not be effective on patients who overdose on this new drug.

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