Robert Cosby Jr. Given Narcan Before Death, Dispatch Audio Reveals

Robert Cosby Jr. was administered Narcan before police reached him ... this according to dispatch audio.

The son of 'Real Housewives of Salt Lake City' star Mary Cosby was not conscious and not breathing Monday, according to the dispatcher ... who then says Robert had been given the opioid overdose countermeasure Naloxone -- brand name Narcan -- already.

Three units were en route to Cosby ... however, we know that once they arrived there was nothing they could do. Page Six was first to report on the dispatch audio.

We broke the story ... emergency medical services received a call about someone experiencing a "full arrest / medical emergency.” EMS pronounced Robert dead at the scene.

Robert had a stressful few months prior to his death ... including an arrest for assault in September and his wife filing for divorce a few months later. He was also arrested for DUI in 2022, a charge to which he later pled guilty.

Mary and Robert had one memorable moment on the show ... an emotional conversation that took place after Robert got married without telling his mom.

Robert was 23.