The over-the-counter herbal drug kratom has been linked to an increasing number of overdose deaths, federal health officials said this week.
Kratom was a cause of death in at least 91 fatal overdoses in the United States from July 2016 to December 2017, and 152 tested positive for the substance in a postmortem toxicology during that time period, health officials found.
Only 44 deaths nationally were previously known, according to Associated Press.
A February study also found that poisonings reported from taking kratom soared more than 50-fold from 13 in 2011 to 682 in 2017 by tracking phone calls about kratom exposures to poison control centers.
While in many of the fatal overdoses, other drugs, like fentanyl or cocaine, were also listed as a cause of death, federal regulators have warned against kratom's use.
What is kratom?
Kratom is a plant grown naturally in Southeast Asian countries including Thailand and Malaysia, where it's been widely used for centuries. It's sold as a powder, typically in capsules, that can be used in tea to ease opioid withdrawals as well as fatigue, pain, coughing and diarrhea.
In the United States, the herbal supplement is typically purchased at smoke shops, gas stations or online.
And its use is increasing in popularity, according to the U.S. Centers for Disease Control and Prevention.
'Significant increase': Poison reports related to herbal drug kratom soar, new study says
But kratom has garnered scrutiny by the Food and Drug Administration, which has said that, like opioids, it carries similar risks of abuse, addiction and in some cases, deaths.
Supporters of kratom, led by the American Kratom Association, have disputed the substance's danger, citing past reports suggesting it has low toxicity and has a milder withdrawal than opiates. They compare the addiction characteristics of kratom to caffeine in coffee.
“Follow the science. Kratom itself is safe," Charles Haddow, the group's senior fellow of public policy, has said.
Why is kratom in the news?
Kratom made headlines this week after the CDC report on rising overdose deaths tied to the herbal supplement.
In seven of the 91 overdoses in which kratom was a cause of death, the herbal supplement was the only substance to test positive in a toxicology report, though the CDC says other substances couldn't be ruled out.
Looking at numbers from state reporting databases, the CDC found 27,338 overdose deaths in the time period, meaning kratom-tied overdoses accounted for less than 1% of fatal overdoses.
Discussing the February study on increased calls to poison centers, Director of the Central Ohio Poison Center Henry Spiller said, "There is a significant increase in the number of cases."
He said the spike is probably the result of greater use, and perhaps larger doses, of a substance that has only recently turned more mainstream.
"There's a general feeling, I think, that this is a natural substance, so it's safe. But we need to get across there are risks with this. If use continues to grow, we're going to see these problems because it is a real potent substance."
Who is using kratom?
Between 3 million and 5 million people use kratom nationwide, according to the American Kratom Association.
Adult men are the most common consumers. The February study found 89% of kratom-related poisonings were among people at least 20 years old, and 71% were among males.
The average age of kratom users was 31 in the study. But of the 1,807 kratom exposures from 2011 to 2017, 137 were among teens between 13 and 19 years old and 48 were among children age 12 or younger.
The study found seven cases resulting from neonatal exposures, a finding that Spiller said was unexpected.
Thirty-two percent of kratom exposure cases among adults resulted in admission to a health care facility while 52% resulted in a serious medical outcome.
What are the possible effects?
According to the National Institute on Drug Abuse, kratom interacts with opioid receptors in the brain to ease pain and produce sedation and pleasure.
Small doses of kratom produce mild stimulant effects, while opioid-like effects occur after moderate to high amounts and sedative effects are associated with very high doses.
Of 1,174 single substance kratom exposures reviewed in the February study, the most common clinical effects were agitation and irritability, tachycardia, nausea, drowsiness and lethargy, vomiting, confusion and hypertension.
According to the report, serious clinical effects included seizures, respiratory depressing, increased bilirubin, bradycardia, rhabdomyolysis, renal failure, respiratory arrest and cardiac arrest.
The report said more research is needed to "define the human response to kratom," but in February, then-FDA Commissioner Scott Gottlieb warned against its use.
"There is no evidence to indicate that kratom is safe or effective for any medical use. And claiming that kratom is benign because it’s 'just a plant' is shortsighted and dangerous," he said in a statement.
How and where is the drug used?
Three-fourths of the kratom exposure cases came after the drug was taken intentionally. But among children 12 or younger, 81% of exposure calls came after unintentional use, the February report found.
Among adults, 60% of reported poisons came after the drug was intentionally abused. The percentage among adolescents was higher at 76%. About 1 out of 10 cases, both adults and adolescents, were attempted suicides.
In 83% of kratom exposures, the drug was taken via ingestion, followed by ingestion through other routes and nasal inhalation.
The majority of cases, 86%, occurred at a residence. States with the highest exposure rates are Idaho, Oregon, Minnesota, New Hampshire and Maine. The lowest exposure rates were found in Wisconsin and Delaware.
Is kratom regulated?
Kratom is currently not scheduled as a controlled substance in the United States.
The Drug Enforcement Administration previously proposed to list it as a Schedule 1 drug, which would ban the substance and put it in the same classification as heroin and LSD, but withdrew the move after backlash.
The Department of Health and Human Services has also previously recommended that kratom be listed as a Schedule 1 drug.
Several states have considered kratom regulations on the state level.
For now, the FDA has not approved kratom for any medical use and the DEA has listed it as a "Drug and Chemical of Concern."
The American Kratom Association is fighting moves to ban the substance, arguing that the FDA has failed to show kratom is dangerously addictive and that it presents a risk to public safety.
The group has said a ban on kratom would potentially increase deaths because many users would turn to dangerous and addictive drugs.
This article originally appeared on USA TODAY: What is kratom and what's it made from? Increasingly popular herbal drug tied to over 90 fatal overdoses