Fentanyl is used to supplement sedation and relieve severe pain during and after surgery,

EEG tests reveal fentanyl's effects on the brain

but it's also one of the deadliest drugs in the opioid epidemic.

According to research, tests of the brain's electrical activity revealed fentanyl's effects over time

and indicated that the drug stops people's breathing before other noticeable changes and before they lose consciousness.

In the study, electroencephalogram (EEG) tests were run for 25 patients undergoing general anesthesia for surgeries lasting 2 hours or more.

The researchers discovered that certain EEG patterns were associated with respiration, sedation, and loss of consciousness.

fentanyl begins to impair breathing about 4 minutes before there is any change in alertness and at 1,700-times lower drug concentrations than those that cause sedation.

at 1,700-times lower drug concentrations than those that cause sedation.but it's also one of the deadliest drugs in the opioid epidemic.

"This explains why fentanyl is so deadly: it stops people's breathing before they even realize it,".