A high school teacher suffered a serious brain injury following a classroom assault by a student, Ohio officials say.

The 16-year-old student was charged with felonious assault after the Thursday, Jan. 4, incident at Colerain High School, according to the Colerain Police Department.

Police said the student began acting “distraught” when they “ingested an unknown drug” at the school, according to WXIX.

The student then punched the teacher “multiple times in (the) head,” Hamilton County Prosecuting Attorney Melissa Powers said in a statement.

“Due to the severity of the assault, (the teacher) was transported to the hospital, where her skull cap had to be removed in order to prevent brain damage due to swelling,” the prosecutor said.

Police said the student, who is also accused of hurting a 15-year-old classmate, was arrested at a nearby career center, WLWT reported.

The teen was ordered to be released from jail, but a judge overruled the decision, prosecutors said.

“Northwest Local Schools has confirmed that the incident was isolated and that there is no current threat to the school community regarding the matter,” police and the school district said in a joint statement. “The district remains resolute in their commitment to providing a safe and nurturing environment for all students and staff.”

Colerain Township is about 20 miles northwest of Cincinnati.