The death of actor Matthew Perry was an accident caused by the “acute effects of ketamine”, a coroner has recorded.

The actor was found unresponsive in a hot tub at his Los Angeles home aged 54 in October.

A post-mortem examination concluded Perry died from the “acute effects of ketamine” while contributing factors included “drowning, coronary artery disease and the effects of buprenorphine”, which is used to treat opioid use disorder.

“The manner of death is accident,” the County of Los Angeles Department of Medical Examiner confirmed on Friday.

Raffi Djabourian, the senior deputy medical examiner, said in his summary: “At the high levels of ketamine found in his post-mortem blood specimens, the main lethal effects would be from both cardiovascular overstimulation and respiratory depression.

“Drowning contributes due to the likelihood of submersion into the pool as he lapsed into unconsciousness; coronary artery disease contributes due to exacerbation of ketamine induced myocardial effects on the heart.”

The widely admired, Emmy-nominated actor, best known for his portrayal of Chandler Bing in Friends, was found dead in his home in Malibu.

At the time, it was announced he was found floating face down in the pool but that no foul play was expected.

The medical examiner said that Perry also drowned in “the heated end of his pool” but that it was a secondary factor in his death.

The report said coronary artery disease and buprenorphine, which is used to treat opioid use disorder, also contributed.

The actor, who was born in Williamstown, Massachusetts, was declared dead at the scene after he was found by his assistant. Investigators performed the autopsy the following day.

Perry had taken drugs in the past but had been “reportedly clean for 19 months,” according to the report.

The coroner said Perry was reported to have been having ketamine infusion therapy to deal with depression and anxiety, and his last treatment was over a week before his death.

Perry had played pickleball earlier in the day, the report said and his assistant, who lived with him, told investigators the actor had not been sick, had not made any health complaints, and had not shown evidence of recent alcohol or drug use.

Perry was open about discussing his struggles with addiction dating back to his time on Friends in the 1990s.

“I loved everything about the show but I was struggling with my addictions which only added to my sense of shame,” he wrote in his 2022 memoir. “I had a secret and no one could know.”

In the days after Perry’s death, his Friends co-stars paid tribute to him.

Jennifer Aniston, Courteney Cox, Lisa Kudrow, Matt LeBlanc, and David Schwimmer said in a statement: “We are all so utterly devastated by the loss of Matthew. We were more than just cast mates.”

They added: “We are a family. There is so much to say, but right now we’re going to take a moment to grieve and process this unfathomable loss.”

The actor was laid to rest at a private funeral service in Los Angeles in November, at a location near the Hollywood studios where they worked together for a decade.