SUDBURY -- A warning is being issued by Sudbury public health officials about pills of fentanyl being disguised as percocet and oxycodone being sold on the streets.

Health officials say if you use oxycodone or percocet that was not prescribed to you, be advised that pills could contain fentanyl and acetaminophen.

Authorities say fentanyl is a powerful opioid, and even a small amount can cause an overdose or be fatal.