Ramsey, Minnesota(CNN) Toxicology tests for Prince concluded that the entertainer died from an accidental overdose of the opioid fentanyl, according to a report on his death by the Midwest Medical Examiner's Office.
Fentanyl, prescribed by doctors for cancer treatment, can be made illicitly and is blamed for a spike in overdose deaths in the United States. It's 25 to 50 times more potent than heroin and 50 to 100 times more potent than morphine, according to the U.S. Drug Enforcement Administration.
Prince, whose full name was Prince Rogers Nelson, died April 21 at age 57, after being found unresponsive in an elevator at Paisley Park, his home and recording studio in Chanhassen, Minnesota.
Opioids and overdoses: 4 things to know
The report from the medical examiner's office, which was released on Twitter, didn't provide many details. "How injury occurred: The decedent self-administered fentanyl," the report said. For manner of death, a box was marked for "accident."
The report didn't specify how the drug was taken and if the fentanyl was prescribed or illegally made.
The music superstar weighed 112 pounds and was 63 inches tall when he died, the report said. He was wearing a black cap, shirt, pants, boxer briefs and socks and a gray undershirt, the report said. His occupation was listed as "artist" and his business as "music."
The full autopsy and toxicology reports will not be released, the office told CNN.
Since his death, information has emerged about the entertainer's alleged abuse of prescription drugs.
A law enforcement source told CNN's Evan Perez in April that the entertainer was found with opioid medication at the time of his death. Investigators so far haven't found any indication that Prince had a valid prescription for the recovered opioid medications
An attorney for Prince's half-siblings said they revealed the singer had an addiction to Percocet decades before he died. One half-sibling said Prince started using the drug to help him deal with the rigors of performing, not for recreational use.
Opioids: Addictive painkillers
Prescription and illegal opioids are commonly abused because they are so addictive.
Opioid medications bind to the areas of the brain that control pain and emotions, driving up levels of the feel-good hormone dopamine in the brain's reward areas and producing an intense feeling of euphoria.
As the brain becomes used to the feelings, it often takes more and more of the drug to produce the same levels of pain relief and well-being, leading to dependence and, later, addiction.
Oxymorphone hydrochloride, under the name Opana ER, was at the center of an HIV outbreak in Indiana in 2015. Some addicts began injecting and shared needles increased the spread of HIV.
In June, the Food and Drug Administration requested that Opana ER manufacturer Endo Pharmaceuticals pull the drug from the market. It was the first time the agency has asked that a opioid pain medication be pulled "due to the public health consequences of abuse." Endo announced in July that it would pull the drug.
Codeine is one of the weakest opioids, often given when painkillers such as acetaminophen or ibuprofen fail to work. Because it decreases activity in the part of the brain that controls coughing, it's frequently mixed with other liquids to develop cough syrups for colds and flu. It has frequently been used for pain relief after removal of tonsils and adenoids in children.
After an investigation, the FDA restricted the use of codeine and tramadol in children under 12 and recommend against their use in children between 12 and 18 years of age. Additionally, the FDA has warned breastfeeding mothers not to take these medications due to the risk of serious adverse reactions in breastfed infants.
You can't get heroin by prescription, but many heroin users start off abusing prescription opioids, then turn to this illegal opioid.
CNN's Chief Medical Correspondent Dr. Sanjay Gupta
has reported on recent research that shows today's typical heroin addict starts using at 23, is more likely to live in affluent suburbs and was likely unwittingly led to heroin through painkillers prescribed by his or her doctor.
According to the CDC, deaths from overdoses of prescription drugs and heroin continue to be the leading cause of unintentional death for Americans, rising 14% from 2013 to 2014.
Fentanyl citrate, pictured here, is a Class II controlled substance and one of the most powerful opioids on the market. It's often administered via injection or transdermal patch, or in lozenge form for pain after surgery, for difficult-to-manage chronic pain and for people who have developed a tolerance to other opioids.
The type of fentanyl usually associated with overdoses is bought on the street in powder or pill form and is often mixed with heroin in a clandestine lab to increase the high it produces. Street names include Apache, China girl, goodfella, jackpot, murder 8, TNT and Tango and Cash.
These pills are a more powerful form of codeine, called hydrocodone, and are often mixed with acetaminophen. Hydrocodone is the most frequently prescribed opioid painkiller,
according to the U.S. Food and Drug Administration, and the most abused. An overdose of hydrocodone can cause "cold and clammy skin, severely constricted pupils, and slow breathing that can lead to a loss of consciousness and death."
Oxycodone is a powerful narcotic pain reliever prescribed for moderate to high pain relief. It's often given in an extended-release formula for patients who will need to be on pain medications for long periods of time.
Patients are warned not to break, chew, crush or dissolve extended-release tablets because the rush of oxycodone into the system could cause serious health problems, including overdose and death.
Though highly addictive, oxycodone is not thought to be as frequently abused as hydrocodone. OxyContin, Percocet, Percodan and Tylox are some trade-name oxycodone products.
Morphine is another powerful opioid often administered via syringe for severe pain. It can come in pill form, usually as extended-release tablets and capsules, and is prescribed only to relieve difficult, chronic pain that cannot be controlled by the use of other pain medications.
As with most opioids, mixing medications, drinking alcohol or taking other meds that contain alcohol, or using street drugs while taking morphine, increases the risk of breathing problems or other serious, life-threatening side effects.
Meperidine is another narcotic analgesic, similar to morphine. It's often used to help put people to sleep before an operation and to provide pain relief after childbirth.
The most common brand name is Demerol, which comes in both tablet and liquid forms. It is usually taken with or without food every three or four hours as needed for pain.
As with all opioids, meperidine can cause drowsiness, so never drive a car or operate machinery after taking it until you know how you will react.
Hydromorphone is another highly potent prescription painkiller. It's most commonly known by the brand names Dilaudid, pictured here, and Exalgo.
Liquid hydromorphone holds the dubious honor of being
frequently mistaken for morphine in hospital "wrong drug" medication errors because of the similarity of the names and appearances.
Though methadone is used to relieve severe chronic pain, it's most commonly known for preventing withdrawal symptoms in patients who were addicted to opioid drugs, as a part of their recovery process.
Methadone has many of the same side effects as other opioids, including weakness, headache, nausea and vomiting, stomach pain, sweating, difficulty urinating, mood changes and vision problems, and difficulty falling asleep or staying asleep.
Buprenorphine is a opioid used as an alternative to methadone to help addicts recovering from heroin use. Buprenorphine is different from other opioids because it's a "partial opioid agonist," which means that when taken in proper prescribed doses, it should produce less euphoria and physical dependence, and therefore a lower potential for misuse. It's also supposed to have a relatively mild withdrawal profile.
However, if abused by crushing and snorting or injecting, it can suppress breathing and cause dizziness, confusion, unconsciousness and death.
Subutex, the brand name for buprenorphine, is taken as a tablet placed under the tongue and allowed to dissolve.
The brand Suboxone is a combination of buprenorphine and naloxone, an opioid antagonist. Antagonists block the opiate receptors in the brain, keeping the narcotic from creating the high abusers crave.
Opioid history: From 'wonder drug' to abuse epidemic
On April 15, on his way home after performing in Atlanta, Prince's plane made an emergency landing in Moline, Illinois. Prince was unresponsive and taken to a hospital. A law enforcement official told CNN he was treated for a potential overdose of pain medication.
Prince's most iconic moments
The day before Prince died, his team called an eminent opioid addiction specialist in California seeking urgent help for the singer, an attorney working for the specialist and his son said.
The specialist, Dr. Howard Kornfeld, couldn't get there immediately so he sent his son, Andrew Kornfeld, on an overnight flight to Minnesota. The goal was for the younger Kornfeld to help evaluate Prince's health and encourage him to enter treatment for pain management and potential addiction issues, attorney William Mauzy told reporters.
Prince's complicated history with painkillers
But by the time Andrew Kornfeld arrived at the singer's Paisley Park complex on the morning of April 21, it was too late. He and two Prince representatives found the 57-year-old entertainer unresponsive in an elevator. Andrew Kornfeld was the person who called 911, Mauzy said.
Authorities have also said the investigation into Prince's death is a criminal investigation. It was not immediately clear if Kornfeld is the subject of a separate investigation.
Federal prosecutors and the Drug Enforcement Administration are investigating how Prince obtained prescription medications and from whom, the agencies said.
CNN's Sara Sidner reported from Minnesota.