A new implant tested in animals reverses drug overdoses

Naloxone has saved thousands of lives by reversing opioid overdoses. But its success depends on someone nearby who can administer the medicine quickly (SN: 5/3/24). Many people are alone when they overdose.

A new implant may one day solve this problem. Inserted under the skin and powered by a battery, the device can detect the onset of an overdose and release naloxone directly into the bloodstream while alerting first responders, researchers reported Oct. 23 in Advances in science. The device, called the Naloximeter, has only been tested on animals.

Researchers hope Naloximetry can help some of the highest-risk individuals: Those who are newly sober, either because they sought treatment or were incarcerated. People are 10 to 16 times more likely to die of an overdose in the first months after a period of sobriety, when their body’s tolerance to opioids has decreased, than they are further into recovery.

In 2023, more than 80,000 people in the United States died of opioid overdose (SN: 25.9.2024). “This problem with fentanyl is getting worse,” says Robert Gereau, a neuroscientist at Washington University School of Medicine in St. Louis. “There is a great need for as many harm reduction efforts as possible.”

Common harm reduction techniques have included safe injection centers and hotlines, but new technologies offer promising alternatives when a bystander cannot be present (SN: 14.2.2024). Until now, apps and other devices can only monitor and alert responders. The naloximeter is the first device that can provide treatment—and do so immediately, in the narrow window when overdoses are still reversible. “That’s where this really shines compared to other interventions,” says Monty Ghosh, an addiction researcher at the University of Alberta in Edmonton, Canada, who was not involved in the study.

The Naloximeter sensor works by measuring the loss of oxygen in the blood – specifically, how fast it is falling and to what level. In a human version of this implant, once an overdose is detected, a warning alert will appear on the person’s cell phone so the person can tell if it’s a false alarm; otherwise, naloxone would be released.

Gereau and colleagues tested two different administration methods in rats and pigs. In trials with pigs, they found that the most effective method was an intravenous catheter, similar to a port used to treat cancer, built into the implant. It delivered 0.7 milliliters of naloxone within 60 seconds, which is “enough to start having a lot of effects on the brain,” says Joanna Ciatti, a materials scientist at Northwestern University in Evanston, Ill.

Although it is still a long way from being tested in human clinical trials and sorting out ethical and logistical concerns, the prospect of such a device is exciting, says Ghosh. Its feasibility will depend on the invasiveness of the implant, its cost and, most importantly, whether people with substance abuse concerns, often wary of interventions, will be open to it.