[nfbush]

Rise in overdoses can be attributed to dealers adding fentanyl (an extrememly strong synthetic opiate) to their product. If a particular salesman has a product which people have reportedly overdosed on will flock to them as they must be selling a stronger product. Another scenario is where the chemical isn't there in the first place and the dealer is simply mixing fentanyl with a filler, due to it's extreme potency (a dose being less than a milligram), making even a small mistake in the mixing can lead to many overdoses especially with tolerant users used to taking larger amounts.

[zkms]

Opioid prohibition ruthlessly selects for opioids that have the highest effectiveness per unit volume -- because traffickers want to make the most profit on uncut material for the same amount of risk.

[pauljaworski]

Fentanyl is actually being synthesized by the Mexican cartels now and added to the heroin before it even makes it to the street dealers. It's getting really crazy.