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A pacemaker-like device that is implanted under the skin and automatically releases an antidote when it detects an opioid overdose could save lives, its designers claim.
The implant has already been successfully tested in pigs. 鈥淚n general, we observe that overdoses treated with the [device] are much less severe, with minimal lasting effects to overall health,鈥� at Northwestern University in Illinois and his colleagues write in their paper.
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In the past two decades, the number of deaths from drug overdoses , largely due to the legal and illegal use of the opioid drug fentanyl. Opioids suppress breathing, causing a fall in blood oxygen levels. If levels drop too low, people die without prompt treatment.
Overdoses can be treated by giving people a drug called naloxone that blocks the action of opioids. A nasal spray containing naloxone called Narcan is available without a prescription in the US. But if people overdose when they are alone, there is no one to administer the naloxone, Rogers and his colleagues write. So, they have designed a device that can be implanted under the skin with a sensor for monitoring blood oxygen levels and a delivery system for injecting naloxone.
It is powered by a battery that can be recharged wirelessly through the skin. The prototype is around 1 centimetre thick, 3 cm wide and 4 cm long, which is smaller than pacemakers, the team writes.
In tests on pigs, it detected overdoses within 1 minute and successfully administered naloxone.
The team envisions the device being implanted in people who have undergone supervised withdrawal, a standard treatment for opioid addiction. There is a high risk of people overdosing in the months afterwards.
鈥淎n automatic system that reliably and accurately detected an overdose and delivered naloxone would save many lives,鈥� says at the National Institute on Drug Abuse in the US. 鈥淗owever, there are challenges.鈥�
People using drugs illegally may not want such a device implanted, so its use could be limited to those taking opioids for medical purposes, she says. This is still valuable since overdose deaths do occur in people being treated with opioid painkillers, says Volkow.
Another issue is that long-term opioid users can tolerate much lower oxygen levels than normal, she says. 鈥淪o it鈥檚 not as simple as detecting a minimal threshold at which you activate the naloxone delivery.鈥�
Wrongly dosing people with naloxone would cause very unpleasant withdrawal symptoms, says Volkow. The implant would also have to be replaced as it contains only a single dose.
鈥淚t鈥檚 a neat idea on paper,鈥� says at the University of Oslo in Norway. 鈥淸But] I鈥檓 not sure if an auto-injector device is the way forward.鈥� A device that calls emergency services when it detects an overdose so a person can receive proper medical care might be a better approach, she says.
Studies of heroin overdoses suggest there is a 20 to 30-minute window for emergency treatment, says Mcdonald. 鈥淭here鈥檚 a decent enough window for intervention,鈥� she says, although it is probably shorter for fentanyl.
If a person who has overdosed doesn鈥檛 get proper medical care, they can stop breathing again when the naloxone wears off after 30 to 90 minutes, she says.
Implanting and removing the device would also be expensive and people might attempt to remove it themselves, says Mcdonald.
bioRxiv
