Mini review: Potential therapeutic values of mitragynine as an opioid substitution therapy

Opioid use disorder (OUD) has become a significant public health issue worldwide. Methadone and buprenorphine are the most common medications used for treating OUD. These drugs have the potential to assist many patients in managing their opioid dependence and withdrawal but they are currently misused and associated with certain compliance issues, side effects, and risk of relapse. As an opioid-like herbal supplement, Mitragyna speciosa Korth or kratom has received increased attention for managing chronic pain and opioid withdrawal symptoms. Nevertheless, the use of kratom as a self-treatment medication for opioid dependence continues to be controversial due to concerns raised about its effectiveness, safety, and abuse liability. The main active alkaloid constituent of the plant, mitragynine, has been shown to act as a partial mu-opioid agonist. Given this pharmacology, studies have been focusing on this psychoactive compound to examine its potential therapeutic values as medication-assisted therapy (MAT). This review aims to provide a current preclinical overview of mitragynine as a prospective novel option for MAT and summarise the recent developments in determining if the plant's active alkaloid could provide an alternative to opioids in the treatment of OUD.