Matthew Perry was found lifeless in a jacuzzi in late October. He was 54 years old.
Drowning is described as a secondary factor in his death. In addition to ketamine, heart problems and buprenorphine – a substance used to treat opioid dependence – are also described as contributing factors.
Perry was best known as the character Chandler Bing on the comedy series "Friends."
According to NPR, Perry was given injections of ketamine as an antidepressant. However, the coroner writes that the last treatment was given about ten days before Perry's death and that it therefore cannot explain why he had the substance in his blood.
Ketamine is also used as a party drug. Overdoses can lead to loss of consciousness or respiratory arrest, NPR writes.