Here's What You Need to Know About Fentanyl, the Powerful Opioid That Killed Prince

Prince's death in April shocked music fans around the world, as did subsequent reports that the 57-year-old pop icon, who famously abstained from drugs and alcohol, died of an accidental opioid overdose. On Thursday, Minnesota officials revealed his exact cause of death: a self-administered overdose of fentanyl, a potent painkiller that has become increasingly popular in both the United States and Canada in recent years, contributing to the surge in fatal overdoses in both countries.

In the US, fentanyl is a lesser-known opioid that has been overshadowed by heroin and OxyContin, two drugs at the root of the country's overdose epidemic. While it's still unclear whether or not Prince was prescribed fentanyl by a doctor, the singer had reportedly been using painkillers, including Percocet, since the mid-2000s, as a result of chronic pain in his ankle and hip from decades of intense stage performances, as well as a 2010 hip surgery.

Fentanyl still isn't a household name like many other opioids, but its role in Prince's death is sure to bring it into the national consciousness. Here's what you need to know about fentanyl.

What Is Fentanyl?
Fentanyl is a synthetic opioid that is typically prescribed to chronic pain patients, or to manage severe pain after surgeries and other medical procedures. It is 50 times stronger than heroin and 100 times more powerful than morphine. In the US, fentanyl — along with other synthetic painkillers like methadone and oxycodone — is a Schedule II controlled substance, meaning it has a high potential for abuse, and can lead to severe psychological or physical dependence.

"It has a significant place in clinical care in that it's a very good drug for individuals who have severe pain, and is often associated with cancer or chronic back pain, when they've been on an opioid for a long period of time," Michelle Arnot, a professor at the Department of Pharmacology and Toxicology at the University of Toronto told VICE News. "It's usually used for people who have already been taking painkillers. One of the issues, and one of the reasons why it's used in those cases, is that it's so potent."

In Canada, the rising popularity of fentanyl has been linked to OxyContin being taken off shelves because the pills could be easily crushed and snorted. When the manufacturer of OxyContin introduced a tamper-resistant version of the drug called OxyNeo in 2012, fentanyl quickly emerged as a popular alternative.

Like other opioids, fentanyl binds itself to the body's opiate receptors, producing feelings of euphoria and relaxation that make it prone to abuse. Other potential side effects, according to the National Institute for Drug Abuse, include drowsiness, respiratory depression and arrest, nausea, confusion, constipation, sedation, unconsciousness, and coma.

"One of the problems is at higher doses, that dampening can be too much and it can lead to respiratory depression, so the signals that go out of the brain to the lungs, to your diaphragm muscles to say, 'breathe,' are basically turned off or turned off so much that individuals … can die," said Arnot.

What Does It Look Like?
When it's prescribed by a physician, fentanyl can come in the form of a lozenge, a "lollipop," or a slow-release patch. It can also be injected. Abusers extract fentanyl gel from patches and lozenges to ingest the drug by smoking, injecting, eating, or dissolving it under the tongue. The drug's powdered form is manufactured in clandestine labs in China and Mexico. It's often compressed into pills or mixed with other drugs like heroin and cocaine, making it difficult to detect and upping its potency.

How Many People Has It Killed?
More than 700 people died of fentanyl-related overdoses from late 2013 to early 2015 in the US, according to the DEA, but that number is likely higher since medical examiners don't always test for the drug.

In 2014, 28,647 Americans died from opioid overdoses, according to data from the Centers for Disease Control and Prevention (CDC). Of those deaths, 18,893 were linked to painkillers like OxyContin, and 10,574 were attributed to heroin. In March 2015, the DEA called fentanyl "threat to public health and safety," and said overdoses linked to the drug were "occurring at an alarming rate."

In Canada, where fentanyl-fueled overdoses have made headlines for months, there were at least 655 deaths in which fentanyl was the cause or a contributing factor between 2009 and 2014, according to Canadian Centre on Substance Abuse. There were also more than 1,000 drug poisoning deaths in which traces of fentanyl were found in the person's system. The western provinces of Alberta and British Columbia have been hardest hit. In April, BC declared a public health emergency after authorities found that fentanyl was involved in more than 200 overdose deaths in the first three months of 2016. If that pace continues, the province could see 800 fatal fentanyl overdoses by the end of the year.

What Can Be Done?
In Canada and in the US, advocates have been pushing for naloxone, a drug that blocks opioid receptors in the brain to quickly counteract overdoses, to become available without a prescription. Just six days before Prince died, he reportedly received the antidote after he overdosed on Percocet, a painkiller that contains acetaminophen and the opioid oxycodone.

Advocates in Canada have also been pushing the government to open safe injection facilities, where fentanyl and heroin users would be allowed to take the drugs under the supervision of health professionals, who can intervene if anything goes wrong.

In March, President Barack Obama proposed spending an additional $1.1 billion to expand treatment programs for opioid addiction, tripling the existing funding in that area. A few weeks ago, the House passed a package of 18 bills on the issue, setting up federal grants and task forces to address everything from opioid addiction to treatment.

Obama also recently sat down with rapper Macklemore, who has been open about his own history with prescription drug abuse, to publicly discuss the crisis. Obama noted that overdoses are often the result of drugs prescribed by doctors.

"So addiction doesn't always start in some dark alley — it often starts in a medicine cabinet," the president said.

Follow Tamara Khandaker on Twitter: @anima_tk

A new VICE on HBO episode about America's heroin crisis airs Friday, June 3 at 11pm ET