A new study finds 10 percent of people saved by the opioid overdose antidote naloxone die within a year of treatment.

“Patients who survive opioid overdoses are by no means ‘out of the woods,’” lead study author Scott Weiner, MD, Director of the Brigham Comprehensive Opioid Response and Education Program at Brigham and Women’s Hospital, said in a news release. “These patients continue to be at high-risk for overdose and should be connected with additional resources such as counseling, treatment and buprenorphine.”

The study, presented at the annual meeting of the American College of Emergency Physicians, found half of patients who died within a year of naloxone treatment died within one month of treatment, HealthDay reports.