Petty, 66, died of multi-system organ failure, resuscitated cardiopulmonary arrest and mixed drug toxicity, according to the coroner's report.
The medications listed in the autopsy report include Fentanyl, oxycodone, and generic Xanax.
Dana and Adria Petty also posted a statement about the news on the Tom Petty and the Heartbreakers Facebook page Friday.
Petty suffered from physical ailments such as emphysema, knee problems and he had significantly fractured his hip, his family said. But despite the hip injury, he toured for 53 dates, which worsened the fracture.
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On Oct. 2, 2017, the day Petty died, he was informed his hip was broken.
"It is our feeling the pain was simply unbearable and was the cause for his overuse of medication," the statement said.
The family went on to say that they knew before the coroner informed them of the overdose that Petty was prescribed several pain medications for his ongoing health issues, and those medications included Fentanyl patches.
"As a family we recognize this report may spark a further discussion on the opioid crisis, and we feel that is a healthy and necessary discussion and we hope in some way this report can save lives," the family's statement said, in part. "Many people who overdose begin with a legitimate injury or simply do not understand the potency and deadly nature of these medications."
They added that Petty was extremely proud of his last tour and for having such loyal fans in his more than 40-year career.
"We continue to mourn with you and marvel at Tom Petty and the Heartbreakers' incredible positive impact on music and the world. And we thank you all for your love and support over the last months," the family said.