UPDATED with cause of death, September 2: The Weld County (Colo.) Coroner said today that Amanda Peterson died of an accidental overdose of multiple prescription drugs including Gabapentin for pain, benzodizepines (anti-anxiety) and phenothiazines (anti-psychotic). The toxicology report said she died from the “morphine effect,” which leads to respiratory failure.

PREVIOUSLY, July 6: TV and film actress Amanda Peterson, best known for 1987 high school romantic comedy Can’t Buy Me Love, died July 5 in Greeley, CO. She was 43.

The cause of her death is not known. Her mother tells CNN her daughter had been treated for heart problems, but the family is awaiting autopsy results to determine the official cause of death. She was married and had been living in Greeley, CO where she grew up.

Peterson started her film career as a child, appearing in the 1982 feature Annie at the age of 9. She went on to appear in the River Phoenix and Ethan Hawke-starrer Explorers in 1985, but she is best known for her role opposite Patrick Dempsey in 1987’s Can’t Buy Me Love.

Her TV credits include a lead role in the NBC drama series A Year In the Life, along with appearances on Father Murphy, Silver Spoons, Doogie Howser and Jack’s Place. She most recently appeared in the 1994 film Windrunner, according to IMDB.