Stephan Bonnar’s death in December was ruled ‘accidental’ on Monday, as a coroner determined the cause as ‘Fentanyl, Parafluorofentanyl and Mitragynine intoxication’.
The UFC Hall of Famer died on 22 December at the age of 45, with ‘presumed’ heart complications referenced at the time.
In a letter to MMA Fighting on Monday (24 April), the Clark County coroner’s office in Nevada said Bonnar had overdosed on Fentanyl, Parafluorofentanyl and Mitragynine.
Fentanyl is a potent synthetic opioid, and along with its analogues – including Parafluorofentanyl – it is reported to have caused the majority of drug-overdose deaths in the US. Meanwhile, Mitragynine is an active alkaloid in the plant Kratom, which can be used for medicinal purposes.
Bonnar made his professional MMA debut in 2001, before fighting in the UFC between 2004 and 2012. He then retired in 2014 after a single bout in Bellator.
Bonnar’s first appearance in front of a UFC crowd came during the first season of the television show The Ultimate Fighter. In the season finale, the American was outpointed by Forrest Griffin while challenging his compatriot for the light-heavyweight title. The fight is widely considered a pivotal moment for the UFC, sparking a period of significant growth among the company’s audience.
Bonnar went on to compile a 15-9 professional record, facing UFC greats Anderson Silva, Jon Jones and Rashad Evans along the way – as well as Griffin a second time, and another UFC champion in Tito Ortiz.
“Stephan Bonnar was one of the most important fighters to ever compete in the Octagon,” said UFC President Dana White at the time of Bonnar’s death.
“His fight with Forrest Griffin changed the sport forever, and he will never be forgotten. The fans loved him, related to him, and he always gave them his best. He will be missed.”
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