While the exact reasons surrounding the death of actor Heath Ledger, 28, will only be determined by further testing, police and forensic pathologists are already looking to drug interactions as a possible culprit.
And as the tales of celebrities who may have died from drug combinations accumulate, stories of people who appear to have indulged in chemical cocktails — and lived to tell about it — are also making the rounds on the entertainment news scene.
In one possible example of this behavior, a home video released this week by the British newspaper The Sun showed singer Amy Winehouse inhaling from a type of glass pipe commonly used to smoke crack cocaine — just a few minutes after she announced that she had taken six tablets of the anti-anxiety drug Valium.
New York-based forensic psychiatrist Michael Welner is chairman of the Forensic Panel, a national forensic science practice that consults on death investigations. He says that a number of factors could affect the likelihood of a given individual dying from a dangerous combination of prescription medicine.
And he notes that recklessness, like that apparently exhibited by Winehouse, is only part of the equation.
"What this says is that this is a person who has the experience of taking drug combinations and waking up the next day and being OK," Welner said. "When people have these types of experiences, they develop their own style of how they take and mix drugs."
With some medications, individuals will find that their tolerance of the drug grows the longer they have been taking it. With time, they may be able to safely take a dose of this drug that would pose a serious hazard for someone who has never taken it.
The specific combination of medications is another factor. Forensic specialists say that when taken together, drugs that have similar effects can conspire to create a more profound effect. A combination of two or three sedatives in their therapeutic doses, for instance, may pack a more dangerous punch than a moderate overdose of any one of the medications alone.
Taking all these factors into account, Welner says the victims of drug cocktails can be divided into one of three recurring types.
"You could have an indulgent person who takes pills in a reckless way, who just pops this pill and pops that pill without regard for the consequences," he says. "You could have an uneducated consumer, who has a certain lack of awareness of what they are doing and who may not be abusing drugs in the way that many people think of, but who takes sedatives and pills in a way that if they were an informed consumer they would not.
"And lastly, you could have a person who takes these medications, maybe even according to the proper doses, but just by the virtue of the unfortunate way in which his body reacts, dies suddenly."
Until the results of the pending toxicology report are released, Welner says, there is no way to tell which, if any, of these categories Ledger fits into.
"[A fatal drug overdose] can happen to someone who is very irresponsible, and it can also happen to someone who is tragically unlucky."
However, the evidence thus far does suggest that a drug cocktail could have been the cause behind Ledger's death.