Feb. 21 (UPI) -- A study published Thursday showed calls to U.S. poison control centers regarding the herbal supplement kratom have increased more than 50-fold in recent years.
The poison control center calls have increased from 13 in 2011 to 682 in 2017. According to the study published in the journal Clinical Toxicology, there were 1,807 exposures across the seven-year period with 65 percent of those intances occurring in 2016-2017.
The herbal supplement has gained national attention as some have reported using the the drug to treat pain and help them refrain from using opioids.
The American Kratom Association has estimated 3 to 5 million people in the United States use kratom.
However, the FDA warns against using the drug and says more research needs to be done to look into it.
"There is no reliable evidence to support the use of kratom as a treatment for opioid use disorder and significant safety issues exist," FDA Commissioner Scott Gottlieb, M.D., said in a statement last year.
Most kratom exposures occurred in adult males, age 20 or older, and were intentional, the study found. There were also 137 exposures in teens, 48 in children under age 12, and seven neonatal exposures.
"Among first-ranked kratom exposures, 31.8 percent resulted in admission to a health care facility and 51.9 percent in a serious medical outcome," the study said.
Eleven deaths were associated with kratom exposure along with other substances. Two of those deaths occurring after exposure to kratom only.
A study by University of Colorado researchers last month reviewed 15 kratom-related deaths and similarly found in all but one, opioids were present.
"Individuals who choose to use kratom need to be aware of the potential risks," said study co-author Henry Spiller of the Central Ohio Poison Center. "Just because it is currently classified as an herbal supplement does not mean that it is regulated or that it is safe."
The FDA announced plans earlier this month to strengthen its regulation of herbal supplements.