After conducting an autopsy as well as a full toxicology screen, the coroner cited atherosclerotic coronary artery disease as the cause of death, and said that the drug test was negative except for a small, "sub-therapeutic" level of hydrocodone, more commonly known as Vicodin.
The department's full report is expected next week, the People magazine reported.
Los Angeles police said they found large empty prescription bottles at Sage's home while investigating his death. The budding filmmaker, 36, was found dead in his apartment on July 13.
Sage was laid to rest on July 21 in Los Angeles.