Researchers at the University of Calgary have discovered that an existing anti-gout medication is effective in reducing the severity of withdrawal symptoms in opioid-dependent rodents and their work is being used to develop a clinical trial.

Opioids are used to treat pain and some people can experience severe withdrawal symptoms when they stop taking them.

"Opioid withdrawal is aversive, debilitating and can compel individuals to continue using the drug in order to prevent these symptoms," said Neuroscientist Tuan Trang. "In our study, we effectively alleviated withdrawal symptoms in rodents, which could have important implications for patients that may wish to decrease or stop their use of these medications."

The team focused its study on morphine and fentanyl and looked at the underlying causes of opioid withdrawal. They identified the target called pannexin-1 and say it is found throughout the body and is responsible for producing withdrawal symptoms in rats and mice.

Experts say that there are few medications to mitigate the symptoms and that the cellular mechanism of opioid withdrawal was not well understood before the study.

"The focus of much of the research so far has been on neurons themselves. Our study looked at key immune cells in the nervous system and specifically at the pannexin-1 channel on these immune cells, which is something that hasn't been explored before," said Trang.

Once scientists identified the mechanism they were able to use the data to test an existing drug, an anti-gout medication called probenecid, to block the effects of pannexin-1.

“So when we treated rodents with the anti-gout medication, which is probenecid, it alleviated many of the signs and symptoms of withdrawal,” said Trang.

The research sheds light on how withdrawal happens and scientists say probenecid is already approved for use, is inexpensive and has few side effects.

They also determined that the anti-gout medication does not affect the pain relief properties of the opioid.

The study was published in the journal Nature Medicine and researchers are now working with the Calgary Pain Clinic to design a clinical trial.