Drug overdose continues to be the leading cause of accidental deaths in Pima County, accounting for 34 percent of inadvertent fatalities, according to a report by the county's Office of the Medical Examiner.

In 2013, 327 people died of an overdose, with 170 of those being between the ages of 40 and 59.

Also, a growing number of those deaths were caused by prescription medication.

“It’s been getting more prevalent over the last few years," said Dr. Gregory Hess, Pima County's chief medical examiner. "Quite a bit has been written about that in the medical literature and how it’s sort of a public health epidemic, in terms of opiate prescription medications.”

Combinations with prescription drugs made from opium caused the most overdose deaths, more than the leading opiate illicit drug, heroin, the report said.

Methamphetamine was the most common single drug for accidental overdose. It was the cause of 78 deaths in 2013. That’s more than double the meth overdoses in 2011 or 2012.

View the full Medical Examiner's report for 2013.