Opioid crises across North America and elsewhere have claimed many lives. In response, researchers have been evaluating safer alternatives to opioid drugs. And according to a new study, their latest candidate might be based on kratom.
American researchers published the study in late June 2021. After noticing kratom's centuries-long history of use as an opioid-like drug, they wanted to explore the plant's clinical applications. Specifically, they were interested in fine-tuning how 7-hydroxymitragynine (7-HMG), a potent kratom alkaloid, binds to opioid receptors in the brain. If they could reduce its "signalling efficacy," 7-HMG could be used to develop safer pain medications.
To do so, the researchers created a substitute alkaloid, 11-Fluoro-7-hydroxymitragynine. They created it by adding fluorine to 7-HMG's chemical structure through a process called fluorination. They then tested this new compound to evaluate its pain-relieving properties.
In rats, a high dose of fluorinated 7-HMG provided rapid pain relief. However, it was less effective than 7-HMG, which had the pain-relieving potency of morphine. While this result might seem disappointing, it has major implications for drug development: Fluorinated 7-HMG is a low-efficacy opioid agonist. And according to the authors, drugs of this class "... are of high interest as candidates for generating safer opioid medications with mitigated adverse effects."
This is because low-efficacy opioid agonists can have therapeutic benefits but fewer side effects compared to other opioids. One example is buprenorphine: As a low-efficacy opioid agonist, it offers pain relief comparable to full agonist drugs like heroin, oxycodone, and morphine, but a decreased risk of respiratory depression and overdose death.
Low-efficacy opioid agonists also have reduced abuse potential. For this reason, they can be used to treat opioid use disorder and other substance use disorders. And as the researchers pointed out, these drugs are also gaining traction as medications for anxiety, depression, and other psychiatric conditions.
In closing, the researchers believe their fluorinated 7-HMG is "... an important lead compound for further investigations." They also note that "... further understanding of kratom and its alkaloids has major implications for public health."