As doctors have started to prescribe Methadone for their patients in higher numbers, deaths from the drug has increased dramatically, 

From the New York Times:

Methadone, once used mainly in addiction treatment centers to replace heroin, is today being given out by family doctors, osteopaths and nurse practitioners for throbbing backs, joint injuries and a host of other severe pains.

A synthetic form of opium, it is cheap and long lasting, a powerful pain reliever that has helped millions. But because it is also abused by thrill seekers and badly prescribed by doctors unfamiliar with its risks, methadone is now the fastest growing cause of narcotic deaths. It is implicated in more than twice as many deaths as heroin, and is rivaling or surpassing the tolls of painkillers like OxyContin and Vicodin.