AUGUSTA — Maine will expand access to a potentially life-saving drug antidote after the bill went into law Tuesday without Gov. Paul LePage’s signature.

The new law allows family members of addicts to be prescribed naloxone, which blocks the brain receptors that opiates latch onto and helps the body take in air.

The law also lets police and firefighters administer the drug, commonly known by the brand name Narcan.

Supporters hailed it as a commonsense way to save lives in Maine, which like much of the country is grappling with a rise in heroin overdose deaths. The number of heroin-related deaths jumped fourfold from seven in 2011 to 28 a year later, according to the state medical examiner’s office.

“Maine decided it must address this public health emergency head-on,” Rep. Sara Gideon, a Freeport Democrat and the bill’s sponsor, said in a statement. “Putting this proven life-saving medication into more hands will save lives and spare families the unthinkable loss of a loved one to a preventable overdose death.”

The Republican governor initially opposed expanding access to naloxone, saying it could provide a false sense of security to abusers if they have a prescription nearby.

He later agreed to provide addicts’ relatives with the drug and allowed the measure to go into law after legislators amended it to require that law enforcement members are trained before they can administer the drug.

Naloxone can be administered through a nasal spray or injection into a muscle. Earlier this month, the Food and Drug Administration approved a device that automatically injects the right dose of the antidote before an ambulance arrives.