Prescription opioids include painkillers such as morphine
Doctors prescribe them for moderate and severe pain
They produce the same effects as heroin, fueling addictions
Deaths linked to opioids are skyrocketing, and so is the number of Americans abusing the drugs, experts say.
Two million Americans were dependent on prescription opioids in 2014, when the most recent data was available, federal statistics show.
Overdoses linked to opioids killed more than 28,000 people nationwide two years ago, according to the Centers for Disease Control and Prevention. The deaths include those involving heroin and prescription drugs such as oxycodone and hydrocodone.
Here are four things to know about these narcotics:
What are opioids?
Opioids are drugs that reduce pain by switching off pain receptors in the brain.