麻豆传媒

NEW ORLEANS -- A large portion of products made with kratom contained more lead than is safe for children and women of child-bearing potential to consume in a day, even at low doses, a review of three independent assessments found.

At the lowest kratom dose of 3 g, 20.6% of products evaluated would exceed a 2.2 mcg/day interim reference level (IRL) -- the threshold of lead exposure recommended by the FDA for children; at the suggested maximum kratom dose of 25 g, 72.1% of products would, reported Rohan Kantesaria, BS Pharm, of the University of Connecticut School of Pharmacy in Storrs, and colleagues, at the American Society of Health-System Pharmacists midyear meeting.

For women of child-bearing potential, 5.9% of the kratom products would exceed their IRL of 8.8 mcg/day at a 3-mg dose, while 54.4% would exceed it at the suggested maximum dose.

Kantesaria told 麻豆传媒 of kratom, "We have to be aware of the fact that it does have these good benefits potentially, but it also has these bad [effects], where people could get addicted, there are adverse events, there are drug interactions, and there is this potential for lead toxicity."

Kratom is made from the dried leaves of the Mitragyna speciosa tree, which grows in Southeast Asia. Available at many convenience stores, smoke shops, and gas stations, it is sold as an energy-booster and touted as a natural tool for pain relief and opioid addiction recovery.

It also has drawn scrutiny for its addictive potential and dangers as an unregulated substance. Its primary active ingredient, mitragynine, has been linked with lethal arrhythmias. The FDA has previously warned that kratom products contain high levels of heavy metals like lead and nickel.

Kratom is in the U.S. as a drug product, dietary supplement, or food additive in conventional food, according to the FDA. The agency has not approved any prescription or over-the-counter drug products containing kratom or its two main chemical components, mitragynine and 7-hydroxymitragyne.

The Drug Enforcement Administration to make kratom a Schedule I controlled substance in 2016 because of its high potential for abuse and adverse health risks, but pushback from advocates for its use led the agency to reverse course.

"When you go to the high doses, that's when you have a concern, especially in children -- this is the worrisome portion because of how it's advertised. And I think that's the thing that could be regulated," Kantesaria said, referring to kratom products on the market that use bright, colorful packaging or come in candy-like gummy forms that might appeal to children.

Michael White, PharmD, also of the University of Connecticut School of Pharmacy and co-author of the paper, told 麻豆传媒 that because kratom contains mitragynine -- what he called a "weak overall opioid stimulant" -- it is "a little like opioid replacement therapy."

Besides lead, he said, some kratom-derived products are formulated to contain high levels of 7-hydroxymitragynine, an alkaloid with high addictive potential, which he said "is potentially really, really dangerous."

White, who is the chair of Kratom Consumer Advisory Council, part of the Global Kratom Coalition advocacy group, said legislators could allow access to users who benefit from kratom, but take steps to prevent them from being harmed. "The least you could do is let people know that there may be heavy metals in products and make a requirement that they get tested," he noted. "And to have proper labeling on your product ... the total amount of alkaloids that you have in the product should be disclosed."

Researchers searched PubMed with prespecified criteria for assessments of kratom-containing products from the earliest possible date to April 2024. They combined three independent assessments where they could determine lead levels in mcg/g of kratom for 68 products. They determined the lead levels for 3 g, 6 g, 9 g, 12 g, and 25 g doses of kratom.

They also analyzed adverse events reported to poison control centers according to age group after kratom-only substance exposure, hospitalizations, and level of care for kratom alone and with other substances, among other outcomes. The most frequent adverse events for those up to 19 years old were agitation, drowsiness, vomiting, and tachycardia. When hospitalized, children under 13 were also more likely to be admitted to a hospital ward than a critical care unit or psychiatric facility, they found.

Correction: This article was updated to include additional information from the FDA.

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