LOS ANGELES — A health alert issued by Los Angeles Unified School District is warning parents about fentanyl-laced drugs that can be purchased online and the dangers to those who take them.

The health alert comes after three students in Santa Monica ingested fentanyl-laced drugs last week and overdosed. Officials said the students thought they were buying ecstasy online. A letter from the school district’s medical director sent to parents on Wednesday said the students suffered “neurological consequences” after ingesting the fentanyl-laced drugs.

“The pills were purchased online and raise significant concern for the growing trend of contaminated illicit drugs and overdoses in Los Angeles County,” it said in the letter.

“We encourage you to have discussions with your child about making healthy choices and about the dangers of ingesting any illicit drugs especially as we enter into end-of-year celebrations and the summer.”

The ages of the students were not released by LAUSD, nor was whether the students took the drugs on district campus grounds.

The three teenage girls overdosed on the drugs at an apartment in Santa Monica last week.

According to the Centers for Disease Control and Prevention, in 2021, overdose deaths involving opioids increased by nearly 40% compared to the year prior. In addition, the LA County Department of Public Health said fentanyl-related overdoses have skyrocketed since the start of the coronavirus pandemic.