A new report finds overdose deaths with evidence of counterfeit pills more than doubled from 2019 to 2021.

Researchers at the Centers for Disease Control and Prevention (CDC) found that overdose deaths involving counterfeit pills accounted for about 5% of overdose deaths, HealthDay reports. They increased from 2% of overdose deaths from July-September 2019 to 4.7% of overdose deaths from October-December 2021. About 75% of these pills were made to look like oxycodone.

Fentanyl was involved in almost all overdose deaths that contained evidence of counterfeit pills. Methamphetamine was also involved in about 25% of deaths involving counterfeit pills.

“Overdose prevention messaging that highlights the dangers of pills obtained illicitly or without a prescription, encourages drug product testing by persons using drugs, and is tailored to persons most at risk (e.g., younger persons) could help prevent overdose deaths,” the CDC said.