Overdose deaths related to the use of the synthetic opioid fentanyl are continuing to rise in Massachusetts.

The Massachusetts Department of Public Health released preliminary data for the first half of 2016 on Wednesday.

The report shows fentanyl-related deaths continue to climb — with 66 percent of 2016's confirmed opioid-related overdose deaths showing a toxicology screen that tested positive for fentanyl.

That's up from 57 percent in 2015.

The report also found that heroin and prescription drug deaths have been decreasing at roughly the same rate that fentanyl has been increasing.

Fentanyl is considered 50 times more potent than heroin.

The report also found that during the first half of 2016, the opioid death rate was higher than in the same period a year ago. (Associated Press)

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