Kratom

The leaves of the herb kratom (Mitragyna speciosa), a native of Southeast Asia in the coffee family, are used locally to relieve pain and improve mood as an opiate substitute and stimulant. The herb is also combined with cough syrup to make a popular beverage in Thailand called “4x100.” Because of its psychoactive properties, however, kratom is illegal in Thailand, Australia, Myanmar (Burma) and Malaysia. The U.S. Drug Enforcement Administration lists kratom as a “drug of concern” because of its abuse potential, stating it has no legitimate medical use. The state of Indiana has banned kratom consumption outright.

Now, looking to control its population’s growing dependence on methamphetamines, Thailand is attempting to legalize kratom, which it had originally banned 70 years ago.

At the same time, researchers are studying kratom’s ability to help wean addicts from much stronger drugs, such as heroin and cocaine. Studies show that a compound found in the plant could even serve as the basis for an alternative to methadone in treating addictions to opioids. The moves are just the latest step in kratom’s strange journey from home-brewed stimulant to illegal painkiller to, possibly, a withdrawal-free treatment for opioid abuse.

Scientific American spoke with Edward Boyer, a professor of emergency medicine and director of medical toxicology at the University of Massachusetts Medical School. These are some of his comments:

Mitragynine—the isolated natural product in kratom leaves—binds to the same mu-opioid receptor as morphine, which explains why it treats pain. It’s got kappa-opioid receptor activity as well, and it’s also got adrenergic activity as well, so you stay alert throughout the day.
Some opioid medicinal chemists would suggest that kratom pharmacology might [reduce cravings for opioids] while at the same time providing pain relief. I don’t know how realistic that is in humans who take the drug, but that’s what some medicinal chemists would seem to suggest.
Kratom also has serotonergic activity, too—it binds with serotonin receptors. So if you want to treat depression, if you want to treat opioid pain, if you want to treat sleepiness, this [compound] really puts it all together.
In animal studies where rats were given mitragynine, those rats had no respiratory depression.
At least one pharma company [Smith, Kline & French, now part of GlaxoSmithKline] was looking at it in the 1960s, but something didn’t work for them. Either it wasn’t a strong enough analgesic or the solubility was bad or they didn’t have a drug delivery system for it.
I don’t know that there are studies showing animals will compulsively administer kratom, but I know that tolerance develops in animal models.