Chris Penn's death has been deemed an accident.
The Reservoir Dogs star and younger brother of Sean Penn was found dead in his Santa Monica condominium on Jan. 24.
Although the Los Angeles coroner examined the body the following day, results of the autopsy and toxicology tests were not made public until Monday.
In a brief statement, the coroner's department said the primary cause of death to be cardiomyopathy--i.e., an enlarged heart--complicated by the "effects of multiple medication intake."
The chief coroner investigator, Craig Harvey, says the official ruling is that the 40-year-old Penn died accidentally.
Harvey said Penn was taking several prescriptions that contributed to his death, most prominently promethazine with codeine. The drug, which is highly addictive, is used to treat serious cold and flu symptoms and most commonly available as a cough syrup, according to WebMD.com. Promethazine is a combination antihistamine and anti-nausea medicine that also works as a sedative. Codeine is also a sedative that is used to curb coughing and reduce pain.
There was no way to tell how much of the medicine that Penn ingested or when he took it, said Harvey. Friends have indicated Penn was battling the flu at the time of his death.
As for the actor's heart, it weighed 700 grams, a few hundred grams more than a typical healthy heart. Penn was not taking heart medication at the time of his death, Harvey said.
Penn also had a history of cocaine and alcohol abuse. As he became sober, his weight ballooned, topping 300 pounds at one point, according to the Los Angeles Times.
A detailed report is expected to be released within a few weeks.
Although eclipsed in fame by his Oscar-winning brother, Chris Penn appeared in more than 70 films and television shows since launching his career in the 1970s, per IMDb.com.
The stocky actor was probably best known for playing Nice Guy Eddie Cabot in Quentin Tarantino's Reservoir Dogs.
Other key credits included Rumble Fish, True Romance, All the Right Moves, Rush Hour and Footloose, where he played Kevin Bacon's two-fisted, two-left-footed best bud, Willard.
In 1986, Penn starred with brother Sean and their mother, actress Eileen Ryan, in the true-crime drama At Close Range. He shared the Golden Globe for Best Ensemble Cast for 1993's Short Cuts.
Penn's final big-screen credits included 2004's Starsky & Hutch and The Darwin Awards, which debuted at the Sundance Film Festival last month.
Following a screening, costar Winona Ryder talked about her fallen castmate.
"I really hope people go back and watch his movies, because he was such a fantastic actor, and he is going to be so missed," Ryder said. "Not just Sean Penn's little brother, you know? He was Chris Penn."
Born in California in 1965, Penn was the son of Ryan and the late Leo Penn, a television director who died in 1998. His oldest brother, Michael, is a musician and actor.
At a funeral service two weeks ago, several stars came out to pay their respects to Chris Penn. Aside from brothers Sean and Michael and their respective spouses, Robin Wright Penn and Aimee Mann, mourners included, per the Los Angeles Times, Jack Nicholson, Charlie Sheen, Tim Robbins, James Gandolfini and Mark Ruffalo.