02/23/2006 at 03:00 PM EST
The body of Chris Penn had Valium, morphine and marijuana as well as an antihistamine and an elevated level of codeine at the time of the 40-year-old actor's death, a toxicology report has determined, TV's Access Hollywood reports.
The official cause of death will remain an enlarged heart, though the substances contributed, says the coroner.
Penn, the younger brother of Oscar winner Sean Penn, was found dead in his Santa Monica condo on Jan. 24.
Penn, who was said to have weighed 300 lbs. At the time of his death, died the same week that his latest film, The Darwin Awards, premiered at the Sundance Film Festival. His other credits included Reservoir Dogs, Starsky & Hutch and Mulholland Falls.