MINNEAPOLIS — Minnesota health officials said there’s been a spike in the number of overdoses from synthetic marijuana in Minneapolis.

Last week alone Minneapolis hospitals handled at least 60 cases related to the synthetic drug, which causes hallucinations and violent behavior in some users and leaves others comatose. Officials said none of the cases has been fatal.

“This is the biggest outbreak in Minnesota that I’m aware of since 2015,” said Jon Cole, medical director of the Minnesota Poison Control System, which monitors drug overdoses. “This alone is going to change the numbers from 2017 and would increase it almost certainly from 2016.”

During an eight-day period beginning Sept. 30, emergency responders had 125 calls in Minneapolis for suspected synthetic marijuana overdoses, said Mike Trullinger, deputy chief of operations at Hennepin Emergency Medical Services.

“Some of these are repeat patients who are literally released from the hospital, go back to the same area and buy more drugs and are again admitted to the hospital,” he said. Many of the overdoses were in downtown Minneapolis.

The agency typically saw two or three such calls a month at the beginning of the year.

According to the 2017 Drug Abuse Trends report, Minnesota had 83 cases of synthetic drug use exposures last year, compared to 223 cases in 2015. The report was compiled by Carol Falkowski, a former director of the Minnesota Department of Human Services’ Alcohol and Drug Abuse Division.

Authorities say regulation is difficult because the drug’s manufacturers regularly change the drug’s recipe to get around laws.

While opioid effects can be reversed with the drug naloxone, there’s no antidote for the various versions of synthetic cannabis, Cole said.