Warning: May cause drowsiness or sudden death syndrome

Heath Ledger's toxicology has now been released two weeks after his tragic death.
Spokeswoman Ellen Borakove stated in a news release:

Mr. Heath Ledger died as the result of acute intoxication by the combined effects of oxycodone, hydrocodone, diazepam, temazepam, alprazolam and doxylamine.

Ledger’s father, Kim, also produced a statement on the matter:

While no medications were taken in excess, we learned today the combination of
doctor-prescribed drugs proved lethal for our boy. Heath's accidental death
serves as a caution to the hidden dangers of combining prescription medication,
even at low dosage.

Kim Ledger, here makes an extremely valid point when he corrently identifies that there are “hidden dangers” regarding prescription drugs. In a related article, Sleeping Pills: Risks and Realities, it is claimed as "fairly standard" to prescribe sleeping pills to anybody with sleeping disorders. Fairly straightforward it would seem, but if given out so freely, should other drugs be as well?

With the unfortunate reaction to the concoction of drugs which cut short Ledger's life and arising career, it would not be a suprise if prescriptions were re-evaluated. However, this has not yet been the case. The "Sudden death symdrome" that is associated with "overdose" or "mixture" of these drugs has, as of yet, had no extensive research and taking that into consideration, should Heath have really been prescribed more than one drug at a time?
The only thing we can be sure about, is that unfortunately for Heath, doctors were not aware of what was to come, and perhaps Heath was simply not educated enough on taking medication.