Heath Ledger's father on his tragic death: "It was totally his fault."

It has been more than eight years since Heath Ledger was found dead in his New York apartment, but the scar of his untimely death still runs deep.

An autopsy would reveal a lethal combination of oxycodone, diazepam, hydrocodone and doxylamine – prescription medications – in the 28-year-old’s body; a mistake that yielded the most tragic consequence.

“It was totally his fault,” the father Heath left behind, Kim, told the Daily Mail yesterday. “It was no one else’s – he reached for them. He put them in his system. You can’t blame anyone else in that situation.”

It's a painful yet unavoidable admission from the 66-year-old Perth businessman.

"That's hard to accept because I loved him so much and was so proud of him."

The Ledger family long feared Heath's laissez-faire attitude towards mixing sleeping pills with pain medication was a dangerous one. Heartbreakingly, they were right.

"His sister was on the phone to him the night before telling him not to take the prescription medications with the sleeping tablets.

"He said: 'Katie, Katie, I'm fine. I know what I'm doing.' He would have had no idea."

It's believed over a quarter of Australians take painkillers at least once a month -  and many are at risk of developing a reliance and addiction.

Kim says those most at risk are busy professionals and high performers who are under high pressure to not take sick leave or holidays. As a wildly successful actor Heath, of course, fit snugly into this category.

Watch a classic Aussie TV moment between Heath and Kath & Kim's Sharon Strzelecki. (Post continues...)

"Because he was travelling a lot, he would pop in to a doctor. In the case of someone with a higher profile it's often a case of 'what do you want' instead of 'what do you need'.

"There's so much pressure on them to perform so even though your body is telling you that it's not good and needs time, it's like 'just take these painkillers and keep going'.

"That was the case with Heath. He had to be back on set to finish (the next day).

"They were doing night shoots in the freezing cold and he had a weak chest anyway. He'd caught this (cough) and just couldn't shake it but he thought he had to because he wanted to get the movie done."

Since his son's death the father has led the not-for-profit organisation, ScriptWise, which aims to prevent prescription medication misuse. Research by the group has found almost half of Australians do not admit to painkiller addiction because they fear judgment.

But the reality remains that addiction does not discriminate.

"It's not selective in any way. That's the frightening thing."

If you or a loved one is suffering with prescription medication addiction, Mamamia urges you to visit ScriptWise.