Kratom in Clinical Practice: What Physicians Need to Know.

Kratom use is increasingly encountered in clinical practice, yet products marketed under this name encompass markedly different substances with distinct pharmacologic and risk profiles. Kratom leaf (Mitragyna speciosa) contains a complex mixture of alkaloids, primarily mitragynine, with serving size dependent stimulant and sedative effects, whereas many modern products labeled as kratom contain concentrated, semi-synthetic, or synthetic alkaloids, particularly 7-hydroxymitragynine (7-OH), with substantially greater opioid-like potency. This review summarizes the pharmacology, clinical effects, and safety data related to natural kratom leaf, contrasts these findings with evidence on high-potency alkaloid products, and examines limitations in adverse event surveillance resulting from exposure misclassification and polysubstance use. Clinical and toxicologic data suggest that severe acute harms attributed to "kratom" disproportionately involve concentrated alkaloid formulations rather than whole-leaf products. Guidance is provided to assist physicians in screening, counseling, and documentation, emphasizing the importance of distinguishing product type to support risk assessment, harm reduction, and patient safety.