Massachusetts regulators are ordering nursing homes to begin stocking the overdose-reversing drug naloxone and to make sure that staff members are trained to care for residents battling addictions, further evidence of the extent of the state’s opioid crisis.

The issue of substance abuse in nursing homes came into sharp focus this year when the Globe reported that state inspectors declared patients in at least two facilities in “immediate jeopardy’’ because of serious violations, including lack of substance abuse treatment and inadequate staff training.

Regulators sent letters in recent weeks to nursing homes noting the “widespread use of opioids’’ for pain relief in these facilities, and reminding administrators of their obligation to admit patients who are fighting addictions.

The guidance came as the nation’s surgeon general issued a sweeping report urging Americans to view substance abuse as a chronic illness, akin to heart disease and cancer, and not a “moral failing.’’

Regulators, advocates, and health industry leaders have spent months spotlighting the state’s opioid crisis, which claimed nearly 1,600 lives last year. But up until now, the problem in nursing homes remained largely in the shadows.

Addiction and long-term care specialists welcomed the state’s initiative, saying few of the roughly 400 nursing homes in Massachusetts are prepared to identify and treat patients with a history of substance abuse, and even when they do, services to care for such residents have typically not been a priority. They say that has left a critical gap for patients who need skilled care, such as rehabilitation after surgery, but who are also are battling addiction.

Dr. Sarah Wakeman, medical director of the Substance Use Disorder Initiative at Massachusetts General Hospital, said she has often struggled to find a nursing home for patients because of stigma associated with the disease, and because of the medications needed to treat it.

“I have seen patients who have had to come off of their addiction medication treatments and risk relapse, or worse, just in order to get into a skilled nursing facility,’’ she said.

As state regulators explained the rules during a recent phone call with nursing home operators, confusion and anxiety were palpable, and questions were abundant. The Globe was allowed to listen to the call.

Nursing home leaders wanted to know whether they are allowed to search rooms of residents who are receiving substance abuse treatment, or to limit their visitors, in hopes of ferreting out illegal substances.

They asked whether they can bar residents from traveling outside the nursing home, and then returning, if they are suspected of using drugs.

And they sought guidance on how to ensure their staff are appropriately trained to care for the increasing numbers of patients, especially younger ones, who are coming through their doors battling addictions.

Regulators’ answers highlighted the fine line nursing home administrators walk in trying to uphold the rights of residents with addictions, while protecting the rest of a facility’s patients.

Regulators said nursing home staffers are not allowed to search patients’ rooms simply because they have a substance abuse history. Nursing homes must provide notice when residents are admitted that they might be subject to a room search, but regulators said residents cannot be expected to waive their rights to privacy as a condition of admission, according to Sherman Lohnes, director of the state health department’s Division of Health Care Facility Licensure and Certification.

Residents have a right to visitors, regulators said, adding that facilities should supervise those visits, especially if the guest is suspected of bringing a patient illicit substances previously.

The requirement that nursing homes stock the overdose antidote naloxone, a drug commonly known by the trade name Narcan, is among the most striking features of the state’s order.

Massachusetts Senior Care Association, the industry trade group, said in a statement that nursing home leaders appreciate the state’s guidance, but more work needs to be done.

“We are hopeful that this . . . is the first step in a collaborative effort to ensure quality care for patients with substance use disorders,’’ said Tara Gregorio, the association’s senior vice president.

Gregorio said the group is working with others to draft legislation “that would allow for safe, quality care for patients with active substance use disorders,’’ but declined to elaborate.

The president of the Massachusetts Medical Society said the organization’s panels on opioid therapy and on geriatric care recently discussed ways to help physicians better address the issue in nursing homes, and is formulating its next steps.

Dr. James Gessner, the society’s president, called the state’s guidance to the nursing home industry a “very reasonable’’ response to the opioid crisis.

“It recognizes that substance use disorders are medical conditions, and that is important to say,’’ Gessner said, “and it recognizes the importance of having people on your staff that can take of them.’’

Kay Lazar can be reached at kay.lazar@globe.com.