Fentanyl is a synthetic opioid. It is 100 times more potent than morphine and 50 times more potent than heroin. Fentanyl is a Schedule 2 drug, meaning that there are some acceptable medicinal purposes however, it is highly addictive. Fentanyl is given in medical settings as a lozenge, transdermal patch, or through a shot. Fentanyl works by binding to the brain's opioid receptors it essentially blocks the body's ability to feel pain. Overdose can happen quickly with fentanyl as it only takes about 2 miligrams (a few grains of salt) to cause a lethal overdose.