The U.S. surgeon general urged Americans to keep the opioid overdose antidote naloxone on hand and get trained to administer it, making the first nationwide advisory in 13 years amid the epidemic.

“It is time to make sure more people have access to this lifesaving medication, because 77 percent of opioid overdose deaths occur outside of a medical setting and more than half occur at home,” U.S. Surgeon General Jerome M. Adams said in a statement today.

The national advisory — the first since the government urged pregnant women to abstain from alcohol in 2005 — follows actions at the local and state levels to give wider access to naloxone, a treatment often sold under the brand name Narcan, a nasal spray. At least 45 states and the District of Columbia now allow naloxone to be obtained without a prescription.

Addiction to opioid drugs including legal painkillers and illegal drugs like heroin, resulted in more than 42,000 overdose deaths in 2016, according to the Centers for Disease Control and Prevention.

The national advisory may give a boost to makers and distributors of naloxone, which is also sold as a handheld auto-injector under the brand name Evzio.

Adapt Pharma Inc., the closely held distributor of the Narcan spray, welcomed the advisory in a statement, saying it’s “committed to expanding affordable access” of its product. Shares of Opiant Pharmaceuticals Inc., a publicly traded company from whom Adapt licenses its sprays, gained 5.5 percent today to close at $19.93.

Pharmacy giant Walgreens Boots Alliance Inc., which stocks Narcan in its more than 8,000 locations nationwide, also supported the advisory.

“We are committed to making naloxone easier to obtain and have taken a number of steps to help curb the rise in overdose deaths,” Richard Ashworth, president of operations at Walgreens, said in a statement.

Kaleo Inc., the privately held maker of the Evzio injector, said it started making the treatment available without a prescription for people who have insurance. The pilot program, available in six states, will be expanded to more, the Richmond-based company said.

Kaleo, which drew attention last year for raising the price of the injector, has taken initiatives to make it more affordable. The company will offer a two-pack of auto-injectors for $360 to federal, state and tribal agencies that purchase the drug directly from Kaleo, company spokesperson Sam Schwartz said. The list price for Evzio is $4,100, but “no patient pays the list price” after accounting for patient assistance programs and insurance coverage, Schwartz said.

The list price for a two-dose package of Narcan is $125, said Thomas Duddy, a spokesman for Adapt Pharma. The company offers a discounts for government, nonprofit organizations, schools and community centers, he said.

Some researchers have said that making naloxone more widely available, while saving lives, could also unintentionally lead to an increase in opioid use as abusers who survived an overdose take more risks. In a study published in March, researchers at the University of Wisconsin-Madison and University of Virginia found that broader access to Narcan led to more opioid-related emergency room visits and theft, and did not not appear to reduce opioid deaths.