The Los Angeles County coroner's office said actress Brittany Murphy's death was caused by pneumonia, and that prescription drug intoxication was also a factor.

Spokesman Craig Harvey said Thursday that the primary cause of Murphy's death was pneumonia, with secondary factors of iron-deficiency anemia and multiple drug intoxication. 

Harvey said the drugs ingested were all prescription medications.

SLIDESHOW: Brittany Murphy: 1997-2009.

Harvey said details of what types of drugs were involved would be released in about two weeks when a complete report is ready.

Murphy died Dec. 20 at age 32 after collapsing at her Hollywood Hills home. 

Her mother and husband said that the actress didn't abuse prescription medications or have an eating disorder.

Murphy's career started in the early 1990s with small roles in television series, commercials and movies. She is best known for parts in "Girl, Interrupted," "Clueless" and "8 Mile."

Her on-screen roles declined in recent years, but Murphy's voice gave life to numerous animated characters, including Luanne Platter on more than 200 episodes of Fox's "King of the Hill" and Gloria the penguin in "Happy Feet."

- The Associated Press contributed to this report.