Is Kratom the New ‘Legal High’ on the Block?: The Case of an Emerging Opioid Receptor Agonist with Substance Abuse Potential

Abstract

Kratom is an unscheduled herbal extract that contains alkaloids with opioid receptor agonist activity. It is currently available in the form of dietary supplements and is used and abused by chronic pain patients on prescription opioids. Active alkaloids isolated from Kratom such as mitragynine and 7-hydroxymitragynine are thought to act on mu and delta opioid receptors as well as alpha 2 adrenergic and 5-HT2A receptors. Animal studies suggest that Kratom may be more potent than morphine. Consequently, Kratom consumption produces analgesic and euphoric feelings among users. Some chronic pain patients on opioids take Kratom to counteract the effects of opioid withdrawal. Although the Food and Drug Administration has banned its use as a dietary supplement, Kratom continues to be widely available and easily accessible on the internet at much lower prices than other opioid replacement therapies like buprenorphine. There are no Federal regulations monitoring the sale and distribution of this substance. Consumption of Kratom has been associated with hallucination, delusion, depression, myalgia, chill, nausea/vomiting, respiratory depression, hepatotoxicity, seizure, coma and death. A search of the pain literature shows past research has not described the use and potential deleterious effects of this extract. Many pain physicians are not familiar with Kratom. As providers who take care of high-risk chronic pain patients using prescribed opioids, knowledge of all current substances with opioid receptor agonists with abuse potential is of paramount importance. The goal of this article is to introduce Kratom to pain specialists and identify issues for further studies that will be required to help better understand the clinical and long-term effects of Kratom use among chronic pain patients. Key words: Opioid receptor agonist, Kratom, Mitragynine, opioid overdose, chronic pain, substance abuse :