Kratom: An Emerging Drug of Abuse
Case Presentation
At his employer’s request, a 33-year-old man presented to his family physician for a worsening of his uncontrolled back pain from a herniated lumbar disk resulting from a motor vehicle collision 3 months before. At his physician’s office he stated, “I don’t care if I live or die, I’m tired of the pain,” and “I’m going to go off on somebody if I can’t get this pain under control.” He also endorsed having auditory hallucinations for several years and a history of violence and homicide. The problem arose precipitously after he became concerned that he was abusing his opioid medication, and it was discontinued. The patient was transferred to the local ED and admitted to the psychiatric service for his suicidal ideations and risk of harming self and others.
On admission to the psychiatric service, the patient complained of body aches, chills, rhinorrhea, and significantly worsened irritability from his baseline, consistent with opioid withdrawal. Initial point-of-care (POC) admission drug testing had been negative as had expanded urine tests looking for synthetic opioids, cannabinoids, and cathinones. The patient reported no opioid use but was unable to explain his current symptom patterns, which were worsening his chronic pain and hampering any attempt to build rapport. On hospital day 3, the patient’s opioid withdrawal resolved, and psychiatric treatment was able to progress fully. On hospital day 4, the inpatient treatment team received a message from the patient’s primary care manager stating that a friend of the patient had found a bottle of herbal pills in the patient’s car. This was later revealed to be a kratom formulation that he had purchased online.
Background
Kratom is the colloquial name of a tree that is native to Thailand, Malaysia, and other countries in Southeast Asia. These trees, which can grow to 50 feet high and 15 feet wide, have long been the source of herbal remedies in Southeast Asia.2,3 The leaves of these trees contain psychoactive substances that have a variety of effects when consumed. At low doses, kratom causes a stimulant effect (akin to the leaves of the coca plant in South America); laborers and farmers often use it to help boost their energy. At higher doses, kratom causes an opioid-like effect, which at mega doses produces an intense euphoric state and has led to a steady growth in abuse worldwide. Although the government of Thailand banned the planting of Mitragyna speciosa as early as 1943, its continued proliferation in Southeast Asia and throughout the world has not ceased.2,3,6
In the United Kingdom, kratom is currently the second most common drug that is considered a legal high, only behind salvia (Salvia divinorum), a hallucinogenic herb that is better known as a result of its use by young celebrities over the past decade.5,8
Kratom can be taken in a variety of ways: Crushed leaves often are placed in gel caps and swallowed; it can be drunk as a tea, juice, or boiled syrup; and it can be smoked or insufflated.2,3,5,6
Pharmacology and Clinical Presentation
More than 20 psychoactive compounds have been isolated from kratom. Although a discussion of all these compounds is beyond the scope of this review, the two major compounds are mitragynine and 7-hydroxymitragynine.
Mitragynine
Mitragynine, the most abundant psychoactive compound found in kratom, is an indole alkaloid (Figure 1). Extraction and analysis of this compound has demonstrated numerous effects on multiple receptors, including mu-, delta-, and kappa-opioid receptors, leading to its opioid-like effects, including analgesia and euphoria. Also similar to common opioids, withdrawal symptomatology can present after only 5 days of daily use. There is limited evidence that mitragynine can activate postsynaptic alpha-2 adrenergic receptors, which may act synergistically with the mu-agonist with regard to its analgesic effect.2,5
7-Hydroxymitragynine
7-hydroxymitragynine, despite being far less concentrated in kratom preparations, is about 13 times more potent than morphine and 46 times more potent than mitragynine. It is thought that its hydroxyl side chain added to C7 (Figure 2) adds to its lipophilicity and ability to cross the blood-brain barrier at a far more rapid rate than that of mitragynine.2
Mitragynine and 7-hydroxymitragynine remain the best-studied psychoactive components of kratom at this time. Other compounds that have been isolated, such as speciociliatine, paynantheine, and speciogynine, may play a role in kratom’s analgesic and psychoactive effects. Animal studies have demonstrated antimuscarinic properties in these compounds, but the properties do not seem to have any demonstrable effect at the opioid receptors.2
Intoxication and Withdrawal
Due to its increasing worldwide popularity, it is now imperative for EPs to be aware of the presentation of patients with kratom abuse as well as the management of withdrawal in light of its dependence potential. However, large-scale studies have not been performed, and much of the evidence comes not from the medical literature but from Web sites such as Erowid or SageWisdom.2,5-9 To that end, such information will be discussed along with the limited research and expert consensuses available in peer-reviewed medical literature.
