CHICAGO (AP) — Chicago now gives at-risk inmates the overdose-reversing drug naloxone upon their release from jail and Los Angeles is poised to follow suit, putting the antidote in as many hands as possible as part of a multifaceted approach to combatting the nation’s opioid epidemic.

The Cook County Jail in Chicago, which is the largest single-site jail in the country, has trained about 900 inmates how to use naloxone nasal spray devices since last summer and has distributed 400 of them to at-risk men and women as they got out. The devices can undo the effects of an opiate overdose almost immediately and are identical to those used by officers in many of the country’s law enforcement agencies.

Sheriff Tom Dart, whose office runs the jail, said addicts are most at-risk of fatally overdosing in the two weeks after getting out because of their time away from drugs while locked up.

“We’ve got to keep them alive (and) if we can get them through that two-week window, they might get treatment, get off drugs,” he said.

Dr. Connie Mennella, the chair of Correctional Health for the county’s health and hospitals system, which administers the program, said only inmates are being trained to use naloxone, but that she eventually hopes their relatives and friends can also be trained.

“We are trying to saturate this community with this drug and we are educating them to tell their buddy, mother, father how to use it, where they keep it and, ‘If you come home and see me not responding, to go get it and use it,’” she said.

Proponents say such jail programs can be the difference between a former inmate living and dying, as the naloxone often can be administered by an overdosing addict, a friend or family member before emergency responders can reach them.

The growing consensus is that naloxone works. Three years ago, the World Health Organization released guidelines recommending expanded naloxone access to people likely to witness an overdose, including drug users. And the North Carolina Harm Reduction Coalition, which tracked the use of naloxone kits by law enforcement, reported that the number of agencies that equip officers with kits climbed from 971 to 1,217 in about eight months last year.

There has been little pushback against efforts to expand the availability and use of naloxone, but there has been some.

Richard Jones, the sheriff of Butler County, Ohio, said this month that he was sticking by his long-standing policy of refusing to allow deputies to carry the drug because he says people can become hostile and violent after being revived by it.

Naloxone also can cause severe opioid withdrawal symptoms.