U.S. law enforcement seized more than 115 million pills containing illicit fentanyl, compared with more than 71 million in 2022, a new study finds.

The number of pills seized in 2023 was 2,300 times greater than the approximately 50,000 seized in 2017, NPR reports.

The fake pills are made to look like prescription opioid medications such as oxycodone or benzodiazepines, according to the study, which was funded by the National Institute on Drug Abuse (NIDA).

“Fentanyl has continued to infiltrate the drug supply in communities across the United States and it is a very dangerous time to use drugs, even just occasionally,” NIDA Director Nora D. Volkow, M.D., said in a news release. “Illicit pills are made to look identical to real prescription pills, but can actually contain fentanyl. It is urgently important that people know that any pills given to someone by a friend, purchased on social media, or received from any source other than a pharmacy could be potentially deadly – even after a single ingestion.”