ALLENTOWN, Pa. (AP) _ A dramatic increase in hospitalizations tied to synthetic marijuana is hitting eastern Pennsylvania, officials said.

The Morning Call reported (http://bit.ly/1HmHdq5) that Sacred Heart Hospital in Allentown and several other hospitals in the Lehigh Valley have been flooded with at least a dozen cases since Saturday.

The drug, known as “fake weed,” is a plant mixture sprayed with a chemical and is marketed as a legal alternative to marijuana. However, authorities warn that there is no control over the chemicals used, and a number of states and the federal government have sought to outlaw the use of those chemicals.

It was not clear what caused the sudden spike in hospitalizations. But Dr. Ryan McClintock at St. Luke’s University Hospital told the newspaper that it could have been a change in the drug’s formulation or a sudden increase in the number of people using it.

Dr. Kenneth Katz, a toxicologist at Lehigh Valley Health Network, told the newspaper that the pediatric unit has been filled with adolescent victims who are sleepy, agitated or experiencing seizures. Katz said they’ve been coming in kicking, screaming and delirious.

Some patients were so agitated they had to be put in restraints and given sedatives, McClintock said.

“There was a period of time when we had used all of the hospital’s large ventilators,” McClintock said. “The (intensive care unit) was actually running out of staff.”

Sacred Heart Hospital became so crowded that ambulances were routed to other facilities.

Allentown appeared to be the hardest hit by the outbreak. Lehigh County District Attorney Jim Martin estimated Allentown had 50 cases since Friday. The Lehigh County coroner’s office was investigating eight deaths in the past week to determine whether they involved synthetic marijuana, Martin said.

In south-central Pennsylvania, authorities in York County said abuse of the substance sent three people to the hospital Wednesday morning. They arrested two people in York with 48 bags of synthetic marijuana, but don’t know how many other packets were sold, they said.

The problem has not just been affecting Pennsylvania. New Jersey State Police posted on their Facebook page that there has been “approximately 400” synthetic marijuana overdoses from Alabama to New York this month.