Bethenny Frankel's Boyfriend's Last Words Help Explain Trump Tower Death

Bethenny Frankel's late boyfriend, Dennis Shields, was able to utter a few words to EMTs and police before he died -- and they paint a clearer picture of how he passed.

Sources say Dennis told the responding EMTs and cops he'd taken some of his prescribed oxycodone as well as Vicodin and a sleeping pill ... all to ease the pain from a back injury.

Doctors warn that opioids should never be taken with sleeping pills or other sedatives. Opioids slow respiratory function and sleeping pills do the same. The two combined can have a dangerous, synergistic effect that could result in death.

As we reported, Dennis' assistant had administered 2 doses of Narcan before authorities arrived. They administered an additional dose of Narcan, but Dennis could not be saved.

Our law enforcement sources say police also found numerous prescription bottles scattered throughout his apartment ... although no illicit drugs nor drug paraphernalia were uncovered.

Bethenny attended Dennis' funeral service earlier this week and dissolved in tears. She paid tribute to both Dennis and her deceased dog, Cookie, on IG.