Updated

The lethal cocktail of drugs that killed actor Heath Ledger two weeks ago could be sitting in your medicine cabinet.

The medications — identified Wednesday as oxycodone, hydrocodone, diazepam, alprazolam, temazepam and doxylamine — are the generic names for the painkillers OxyContin and Vicodin, the anti-anxiety drugs Valium and Xanax and the sleep aids Restoril and Unisom.

Ellen Borakove, a spokeswoman for the New York City medical examiner, who conducted the autopsy, said Wednesday that the cumulative effects of these combined prescription medications killed the 28-year-old Australian-born actor.

"The danger is that all these drugs have similar side effects and they tend to add up," said Dr. Manny Alvarez, managing editor of health for FOXNews.com.

Five of the drugs found in Ledger's system were prescription, only doxylamine — an antihistamine used for sleep — can be purchased over the counter, said William McCloskey, vice chair of the department of pharmacy practice for the Massachusetts College of Pharmacy and Health Sciences.

Oxycodone, a painkiller, and hydrocodone, a cough suppressant and painkiller, are narcotics, McCloskey said. Diazepam, alprazolam and temazepam are from the sedative family, with the first two drugs typically prescribed for anxiety and the third for sleep.

"All of these drugs, all six of them, can suppress the central nervous system and certainly cause respiratory depression, as well, if taken in large enough doses," McCloskey said.

"Typically, you'd not see these drugs prescribed by the same individual in the same patient," he said.

The drugs' combined side effects could cause dizziness and loss of consciousness, Alvarez said. "It could also lead to heart-rhythm irregularities."

Problems begin when people start hoarding the drugs in their medicine cabinets — a telltale sign of addiction, Alvarez said.

"People covet these medications," Alvarez said. "They try to get refills so they have all these medications in their home, and then they begin to self-medicate."

Ledger's body was discovered by his masseuse on Jan. 22 after she arrived for an afternoon appointment. She entered his bedroom to set up for the massage and found him unresponsive. Ledger had been dead for some time, and police say no foul play occurred.

"If you have an addictive personality and you need pills, and you have multiple doctors that don't know what each is prescribing," Alvarez said, "ultimately you could have this accidental overdose, which is what happened to Heath Ledger."

The bottom line, said Alvarez: "Always disclose the medications you're taking with any physician to avoid a potentially deadly situation."

FOXNews.com's Sara Bonisteel and The Associated Press contributed to this report.

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