What is ketamine, the drug involved in Matthew Perry's death?

The investigation into the death of “Friends” star Matthew Perry has led to a sweeping indictment that pulled in five people who prosecutors say contributed to his ketamine overdose in October, including two doctors and a street dealer involved in providing Perry large amounts of the powerful anesthetic.

Here's what to know about ketamine.

Ketamine is a powerful anesthetic approved by U.S. health regulators for use during surgery. It can be given as an intramuscular injection or by IV.

The drug is a chemical cousin of the recreational drug PCP. Ketamine itself has been used recreationally for its euphoric effects. It can cause hallucinations and can impact breathing and the heart.

Ketamine has seen a huge surge in use in recent years as a treatment for depression, anxiety and pain. While the drug isn’t approved for those conditions, doctors are free to prescribe drugs for so-called off-label uses.

In Perry's case, he was using it to treat depression. He was receiving ketamine infusion therapy from his physicians, but prosecutors said the actor turned to other sources when his doctors refused to give him more doses.

Prosecutors said Thursday that Perry obtained ketamine illicitly through a network that included a pair of doctors, his assistant and a woman they dubbed the “Ketamine Queen.” Perry’s assistant, who has pleaded guilty to one count of conspiracy to distribute ketamine causing death, injected the actor with ketamine — including several times on the day he died.

“We are not talking about legitimate ketamine treatment,” U.S. Attorney Martin Estrada said while announcing the charges. “We’re talking about two doctors who abused the trust they had, abused their licenses to put another person’s life at risk.”

Ketamine also has been used by paramedics as a sedative, often while working alongside police when they believed subjects were out of control. Some states and agencies have begun to rethink the practice due to its dangers. The 2019 death in Colorado of a young Black man named Elijah McClain brought scrutiny to the practice and led to a pair of paramedics being convicted for giving McClain an overdose of ketamine.

Overall, the practice of giving ketamine and other sedatives to people detained by police has spread quietly across the nation over the last 15 years, built on questionable science and backed by police-aligned experts, an investigation led by The Associated Press has found.

The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Science and Educational Media Group. The AP is solely responsible for all content.

United States Attorney Martin Estrada, at podium, takes questions from the media after announcing court filings related to the death of actor Matthew Perry in Los Angeles on Thursday, Aug. 15, 2024. (AP Photo/Damian Dovarganes)

FILE - Actor Matthew Perry participates in the BUILD Speaker Series to discuss the mini-series "The Kennedys After Camelot" in New York on March 30, 2017. (Photo by Evan Agostini/Invision/AP, File)

DAKAR, Senegal (AP) — President Bassirou Diomaye Faye of Senegal promised severe sanctions against people smugglers during his visit on Wednesday to the town of Mbour, the departure point of a boat that capsized on Sunday, killing at least 37 people.

“We will relentlessly track down and punish with the greatest severity the actors who organize these convoys of death,” Faye said.

Mbour, a coastal city in Senegal nearly 80 kilometers (50 miles) south of the capital Dakar, is one of many places from which young Senegalese people embark on a treacherous journey to Europe, trying to cross the Atlantic Ocean in pirogues, artisanal fishing boats.

One of these boats heading to Europe left Mbour on Sunday afternoon before capsizing a few miles (kilometers) off the coast.

There were 89 people on board, Faye said, and at least 37 died. Only three survivors have been found so far.

“Your life is of inestimable value," Faye told Mbour's residents on Wednesday. “You have a central role to play in the future of our country. We are determined to offer you real and dignified opportunities, here, at home, so that this sea never again becomes a cemetery for our children.”

The French Navy is continuing to search for other bodies, and the captain and owner of the pirogue was arrested after he turned himself in on Monday.

In recent years, the number of migrants leaving West Africa through Senegal has surged with many fleeing conflict, poverty and a lack of jobs. Most head to the Canary Islands, a Spanish archipelago off the coast of West Africa, which is used as a stepping stone to continental Europe.

Last month, the Senegalese army said it had arrested 453 migrants and “members of smuggling networks” as part of a 12-day operation patrolling the coastline. More than half of those arrested were Senegalese nationals, the army said.

In July, a boat carrying 300 migrants, mostly from Gambia and Senegal, capsized off Mauritania. More than a dozen died and at least 150 others went missing.

The Atlantic route from West Africa to the Canary Islands is one of the deadliest in the world. While there is no accurate death toll because of the lack of information on departures from West Africa, the Spanish migrant rights group Walking Borders estimates the victims are in the thousands this year alone.

Migrant vessels that get lost or run into problems often vanish in the Atlantic, with some drifting across the ocean for months until they are found in the Caribbean and Latin America carrying only human remains.

After migrant boat tragedy, Senegal's president vows sanctions against people smugglers

FILE - Children play on fishing boats known as "pirogues" in Dakar, Senegal, June 24, 2023. Large pirogues are used in migrant crossings from Senegal to Spain. (AP Photo/Zane Irwin, File)

After migrant boat tragedy, Senegal's president vows sanctions against people smugglers