Kratom: A growing substance of abuse in the United States.

Background: Use of kratom is increasing in the United States due to its perceived safety as a botanical product. This review provides salient information about kratom for the practicing clinician.

Methods: We conducted a literature search of MedLine, UpToDate, and Google using the terms "kratom" and "Mitragyna speciosa" for articles published within the last 10 years.

Results: We reviewed > 500 articles. Kratom is derived from the Mitragyna speciosa plant of Southeast Asia. It has grown in popularity within the United States due to its dual effects of acting as a stimulant at low doses and acting as an opioid-like substance at higher dosages. The 2 major active ingredients in kratom, mitragynine and 7-OH mitragynine, act as partial agonists at the mu-opioid receptor. While adverse consequences are normally mild, there are several potentially serious adverse effects, including respiratory depression, especially with chronic, high-dose usage. Furthermore, in case reports, concomitant use of kratom with other substances has been linked to seizures. Unfortunately, an increasing number of deaths have been linked to kratom usage. Six states have made it illegal to possess or sell kratom.

Conclusions: Kratom is an emerging drug of abuse in the United States. Its use is increasing in individuals who may seek to experience an opioidlike "high" as well as to help reduce withdrawal effects from other opioids.