TAZEWELL COUNTY -- It's called methadone, which is similar to Vicodin or Oxycontin.
Tazewell County Coroner Carl Powell says the drug is used to treat not only pain, but also if someone overdoses on heroin.
Powell says the drug can be particularly dangerous in those who mix the drug with anti-depressants or anxiety medications.
"What happens with the Methadone is your brain swells due to being over intoxicated on the Methadone or the other drugs, and when your brain swells it has nowhere to go, and so when it swells, it causes the brain stem to push up against your spinal column which takes care of the breathing and the life functions of the heart and it shuts those things down," said Powell.
Powell says of the six people who died due to an overdose, three of them used other drugs in combination with the Methadone.