"Drug use was heavily implicated" in Presley's death, writes Guralnick. "No one ruled out the possibility of anaphylactic shock brought on by the codeine pills ... to which he was known to have had a mild allergy." A pair of lab reports filed two months later each strongly suggested that polypharmacy was the primary cause of death; one reported "fourteen drugs in Elvis' system, ten in significant quantity." Forensic historian and pathologist Michael Baden views the situation as complicated: "Elvis had had an enlarged heart for a long time. That, together with his drug habit, caused his death. But he was difficult to diagnose; it was a judgment call."
The competence and ethics of two of the centrally involved medical professionals were seriously questioned. Before the autopsy was complete and toxicology results known, medical examiner Dr. Jerry Francisco declared the cause of death as cardiac arrhythmia, a condition that can be determined only in someone who is still alive. Allegations of a cover-up were widespread. While Presley's main physician, Dr. Nichopoulos, was exonerated of criminal liability for the singer's death, the facts were startling: "In the first eight months of 1977 alone, he had more than 10,000 doses of sedatives, amphetamines and narcotics: all in Elvis's name." His license was suspended for three months. It was permanently revoked in the 1990s after the Tennessee Medical Board brought new charges of over-prescription.
In 1994, the Presley autopsy was reopened. Coroner Dr. Joseph Davis declared, "There is nothing in any of the data that supports a death from drugs. In fact, everything points to a sudden, violent heart attack." Whether or not combined drug intoxication was in fact the cause, there is little doubt that polypharmacy contributed significantly to Presley's premature death.