Interior Health is issuing a drug alert for Penticton on Friday, Dec. 13.
The regional health authority says the alert was issued after a purple substance "sold as down" tested positive for medetomidine and fentanyl.
IH added that the drug looks like purple chunks and pebbles and carries a high risk of overdose and prolonged sedation.
While fentanyl responds to naloxone, medetomidine will not, Interior Health said in its drug alert.
"This can lead to complicated and long-lasting overdose symptoms," the alert reads. "Medetomidine suppresses respiration and has potentially dangerous cardiovascular effects."
IH is asking people to call or text 236-422-1601 if they have a drug that fits the description.
The alert is in effect until Dec. 20.
