US Pharm. 2015;40(3):16-17.

Drugs that selectively target the melatonin MT2 receptor represent a novel class of analgesic drugs that could be used to treat patients with neuropathic pain, according to results of an international study led by scientists at McGill University. An estimated 7% to 8% of adults worldwide suffer from neuropathic pain, and 5% of these cases are severe. The situation holds great economic implications, including reduced productivity and large health care costs.

A team led by Dr. Gabriella Gobbi, Associate Professor in the Department of Psychiatry of McGill’s Faculty of Medicine, has demonstrated that UCM924, a melatonin MT2 receptor drug, relieves chronic pain in animal models; the scientists have also identified the drug’s mechanism of action in the brain. UCM924, by activating the MT2 receptors in the periaqueductal grey (a brain area controlling pain), is able to switch off the neurons that trigger pain and switch on the ones that turn off pain. The findings are reported in the February issue of the journal PAIN.

“There are very limited treatments available for neuropathic pain, and a lot of patients use opioids,” says Dr. Gobbi, who is also a researcher at the Research Institute of the McGill University Health Centre (RI-MUHC). “In the long term, these can lead to addiction and severe side effects, including dependence and tolerance, opioid-induced hyperalgesia (the pain becomes even worse), and risk of death. For these reasons, identifying novel analgesics is of keen interest in the medical field today.”