The incident occurred on May 30, when Deputy Kevin Singleton and Deputy Marlene Castellanos of the Transit Services Bureau were conducting a check of the Metro L Line's Fillmore train station platform.
They found a man slumped over on a bench, and Singleton made a radio call requesting paramedics at the scene.
While waiting for the paramedics to arrive, the deputies decided to administer Narcan, a device that delivers the opioid-overdose antidote naloxone.
"Narcan's important to us because it helps -- we never know who we're actually going to come across," Castellanos told ABC7 in an interview.
The deputies administered two doses of Narcan, and the man became responsive.
Paramedics arrived and transported the man to a hospital. Authorities said he made a recovery.
"Had we not had that Narcan handy," Castellanos said, "who's to say what could have happened to this individual while we waited for paramedics to arrive?"
Since the COVID-19 pandemic, Transit Services Bureau deputies have been carrying three doses of Narcan each day, officials said.