Animal studies suggest its opioid effect could help treat pain. Respiratory depression has not been reported with kratom as with other opioids, he said, but it has been found to disrupt a liver enzyme that helps metabolize opioids, he said. For that reason, if drug users went off prescription narcotics or heroin in favor of kratom, but then went back to their previous drugs, kratom might be "increasing the deadliness of the other opioids that you were taking."