THE BURNED OVER DISTRICT

Then you are most definitely stupid enough to go the next step and shoot up fentanyl. You problem would be you are not smart enough to know how pure it may be and how long you have left to live.

Fentanyl, which looks like heroin, is a powerful synthetic painkiller that has been laced into heroin but is increasingly being sold by itself — often without the user’s knowledge. It is up to 50 times more powerful than heroin and up to 100 times more potent than morphine. A tiny bit can be fatal.

In some areas in New England, fentanyl is now killing more people than heroin. In New Hampshire, fentanyl alone killed 158 people last year; heroin killed 32. (Fentanyl was a factor in an additional 120 deaths; heroin contributed to an additional 56.)

“It sort of snuck up on us,” said Detective Capt. Robert P. Pistone of the Haverhill Police Department in Massachusetts. He said that a jump in deaths in 2014 appeared to be caused by heroin, but that lab tests showed the culprit was fentanyl.

Fentanyl represents the latest wave of a rolling drug epidemic that has been fueled by prescription painkillers, as addicts continue to seek higher highs and cheaper fixes.

“It started out as an opioid epidemic, then heroin, but now it’s a fentanyl epidemic,” Maura Healey, the attorney general of Massachusetts, said in an interview.

Fentanyl has been used since the 1960s in medical settings to treat extreme pain on a patch or in a lozenge. In recent decades, illicit fentanyl has seeped into the United States from clandestine labs in Mexico.

“For the cartels, it’s their drug of choice,” Ms. Healey said. “They have figured out a way to make fentanyl more cheaply and easily than heroin and are manufacturing it at a record pace.”

Cheap and you can cut the hell out of it and still keep the junkies happy. But there is always a way to go one step to far and with fentanyl that is just a little step farther. And so it has gotten that much easier to clean the gene pool.