Florida toxicology study links mitragynine detection to drug-toxicity deaths

Why it matters

A large Florida medical-examiner study found an association between mitragynine detection and drug-toxicity deaths, usually involving other substances. It supports closer toxicology surveillance, but cannot show how often kratom causes death or estimate risk for people who use it.

The big picture

Mitragynine is a principal kratom alkaloid. Detecting it after death establishes exposure, not the dose taken or its contribution to a death. This retrospective study compared selected medical-examiner cases with available toxicology records, rather than following kratom users and nonusers over time.

Key findings

• Researchers analyzed 61,234 Florida medical-examiner cases from 2020 through 2023 with at least one substance documented in the available toxicology record; these were not all deaths in Florida.
• Mitragynine was documented in 1,133 cases. Of those, 1,053, about 93%, had multiple substances detected, and 965 were classified as drug toxicity-related deaths.
• Mitragynine detection remained associated with higher odds of a drug toxicity-related classification after adjustment for other substances and demographic and health factors. The association does not establish that mitragynine caused those deaths.
• The records lacked quantitative alkaloid concentrations, dose and timing information, and product composition. The findings cannot distinguish the risks of botanical leaf from concentrated or adulterated products.
• Testing was not known to be uniform across cases. A case without another documented substance was not proof of kratom-only exposure, and selection and unmeasured confounding limit generalization to living users.

What they say

The authors state: “detection of mitragynine in postmortem toxicology does not establish that it directly caused or contributed to death.” They disclose that Oliver Grundmann and Christopher McCurdy serve as expert witnesses in kratom wrongful-death lawsuits.

Bottom line

Mitragynine detection marked higher odds of drug-toxicity deaths in this selected Florida cohort, mostly with other substances present; the study does not establish causation or population-level risk.