Report: Stephan Bonnar Died Due to Accidental Fentanyl Overdose

UFC Hall of Famer Stephan Bonnar’s death late last year was a result of an accidental fentanyl overdose.

The Clark County (Nev.) coroner’s office informed MMAFighting.com via email that Bonnar’s death was a result of “Fentanyl, Parafluorofentanyl and Mitragynine intoxication.” Bonnar died on Dec. 22 at 45 years old. Further details regarding Bonnar’s death were not available due to medical privacy laws.

According to DEA.gov, fentanyl is a “potent synthetic opioid drug approved by the Food and Drug Administration for use as an analgesic (pain relief) and anesthetic. It is approximately 100 times more potent than morphine and 50 times more potent than heroin as an analgesic.” Fentanyl has been linked to numerous overdoses in the United States and is currently a focal point of the country’s opioid crisis.

The UFC initially announced Bonnar’s passing in a statement, adding that the cause of death was “presumed heart complications while at work.”

Bonnar is perhaps best known was his time on “The Ultimate Fighter 1,” where he reached the finals of the reality show and received a UFC contract after losing a unanimous decision to Forrest Griffin in a memorable clash on April 9, 2005. That bout was later enshrined in the UFC Hall of Fame’s “Fight Wing.”

That led to a seven-year career with the Las Vegas-based promotion that saw “The American Psycho” compile an 8-7 mark in the Octagon. He earned wins over the likes of Keith Jardine, James Irvin and Krzysztof Soszynski and also squared off against noteworthy foes such as Anderson Silva, Jon Jones, Mark Coleman and Rashad Evans.

Bonnar initially announced his retirement following a loss to Anderson Silva at UFC 153 in October 2012, but he made a brief return to MMA two years later, falling to Tito Ortiz via split decision at Bellator 131 on Nov. 15, 2014.