Across Washington state, addiction specialists are working to help people who use the potent opioid fentanyl access treatment for substance use disorder.
In 2025, King County reported that more than 700 people just within the county died of overdoses that involved fentanyl. Even though fentanyl can be deadly, people using it may be hesitant to start treatment because doing so can involve going through opioid withdrawal.
A new study has found that low doses of the sedative ketamine can help relieve symptoms of fentanyl withdrawal. Researchers believe this could help patients avoid the uncomfortable side effects of medication used to treat opioid use disorder.
The study, published in the journal Addiction Science & Clinical Practice, involved 50 patients at a crisis center in Mobile, Alabama.
The patients, who reported that they had recently used fentanyl and were in moderate withdrawal, were injected with a small amount of ketamine. Ketamine is a dissociative drug often used by healthcare providers as anesthesia. It can also produce hallucinogenic effects and is used illicitly as a recreational drug.
After receiving the ketamine injections, patients were given the medication buprenorphine a short time later. Buprenorphine is used to treat opioid use disorder, but it can initially trigger intense withdrawal symptoms, making some patients hesitant to take it despite its effectiveness.
Dr. Lucinda Grande, an author of the study, is a clinical associate professor at the University of Washington School of Medicine. She specializes in chronic pain and addiction treatment.
Opioid withdrawal is extremely uncomfortable; Grande said it can include intense anxiety and painful symptoms.
“It can be really, really awful, and people say they'd rather die than go through this,” she said. “They have intense bone pain, muscle pain, stomach upset that’s like incredible painful cramps. They get vomiting and diarrhea."
However, 49 of the 50 patients in the study who took ketamine reported that they began to feel better an hour after receiving the sedative. Many saw their symptoms nearly or completely clear up. According to Grande, it's notable that patients had an easier transition to buprenorphine and experienced relief from withdrawal symptoms after receiving a low dose of ketamine.
Researchers have found that higher doses of ketamine can help reverse opioid withdrawal but cause patients to get extremely drowsy, according to UW Medicine.
In this study, though, Grande said patients were given “such a small dose that they don’t even notice anything except that their fentanyl withdrawal essentially resolves.”
The study is building on evidence that ketamine can be used to treat chronic pain and a variety of behavioral health issues, including depression.
Dr. J. Luke Engeriser, the lead author of the article, conducted the study at the Alabama crisis center. He pursued this research because he wanted to improve treatment for patients addicted to fentanyl.
To avoid negative side effects in the past, patients at Engeriser’s clinic would sometimes have to wait days for the potent opioid to leave their system before receiving buprenorphine.
“Very simply, what we were doing wasn't working,” he said. “It was taking too long, it was too miserable for our patients, and wasn't that successful. So we needed a new strategy.”
His study found that the ketamine injections shortened patients' time at the crisis center when receiving buprenorphine. According to the study, patients who were not given ketamine would stay at the crisis center for 66 hours on average. But for patients who had received a ketamine injection before being given buprenorphine only had to stay for seven hours on average.
"What an advantage to the patients, to be able to take something that would take days to, in most cases, get finished within a matter of hours," Engeriser said.
According to Engeriser, the ketamine treatment is now being widely offered to patients at his clinic who come in for fentanyl treatment. He said some refer to it as “rapid detox.”
Grande, with UW, is now working to develop a study to look at how continuing to administer ketamine over a longer period of time may affect patients. She hopes those findings will inspire more medical providers to use ketamine to address fentanyl withdrawal and make addiction treatment less intimidating for patients.
