DAWSON CREEK -- Northern Health has issued an overdose alert for Northern B.C.

This alert follows an increase of overdose events in the region.

Public health authorities say these overdoses are stemming from a substance sold as down.

This substance is highly toxic and could be contaminated with benzodiazepine, which includes a heavy and prolonged sedation and requires more naloxone to reverse the effects.

Northern Health says the first signs of an overdose are choking, gurgling and snoring sounds.

Residents are being advised to get overdose prevention, recognition and response training; carry naloxone.