Understanding Kratom Use: A Guide for Healthcare Providers

Kratom addiction per DSM-5 SUD criteria, and kratom physical dependence: Insights from dosing amount versus frequency

BACKGROUND

Kratom products are widely used in the United States, with inadequate understanding of how dosing amounts/frequencies relate to outcomes.

METHODS

Between July-November 2022, we enrolled 395 active US adult kratom consumers into a remote study with a baseline survey. We examined self-reported typical dose amounts and frequencies across people and product types, and their associations with outcomes: multiple regression was used to examine whether amounts and frequencies (doses/day) were associated with acute effects, withdrawal symptoms, scores on the Subjective Opioid Withdrawal Scale (SOWS), and addiction (operationalized as DSM-5-based symptoms of kratom-use disorder, KUD).

RESULTS

Participants were 54.9% male, aged 38.1 on average, and 81.3% White. Mean length of kratom use was 5.7 years. Most (95.9%) reported regularly using whole-leaf kratom products; 16 (4.1%) reported regular extract use. SOWS scores were mild to moderate on average (13.5, SD 11.9). KUD symptom counts were mostly in the mild/moderate range (80.7%). Withdrawal and KUD symptoms were more closely associated with dose frequency than dose amount. Men reported more acute effects, withdrawal symptoms with cessation, and KUD symptoms than women.

CONCLUSIONS

Greater dose amount and frequency were systematically related to the number of withdrawal symptoms upon cessation and to KUD symptoms; the relationship was stronger for dose frequency than amount. Men may have more acute effects and more withdrawal and KUD symptoms than women. Although kratom may be used nonproblematically by some consumers, physical dependence (tolerance, withdrawal, or use to avoid withdrawal) and KUD become more likely with increasing dose frequency.

Kratom (Mitragyna speciosa) Use and Mental Health: A Systematic Review and Multilevel Meta-Analysis

INTRODUCTION

Kratom (Mitragyna speciosa) is a medicinal tree native to Southeast Asia. The present multilevel meta-analysis describes the association between kratom use and the positive and negative indicators of mental health.

METHODS

A total of thirty-six articles were included in the meta-analysis to examine the associations, using a random-effects model.

RESULTS

The pooled effect size showed a very small positive association between kratom use and negative indicators of mental health {r = 0.092, 95% confidence interval (CI) = [0.020, 0.164], p < 0.05}, while no significant association was found with positive indicators of mental health (r = -0.031, 95% CI = [-0.149, 0.087], p > 0.05). Pooled effect sizes of specific mental health outcomes indicated that kratom use showed only a small positive correlation with externalizing disorders (r = 0.201, 95% CI = [0.107, 0.300], p < 0.001). No significant association was found between kratom use and quality of life (r = 0.069, 95% CI = [-0.104, 0.242], p > 0.05) and internalizing disorders (r = -0.001, 95% CI = [-0.115, 0.095], p > 0.05). Multilevel moderator analysis showed that the pooled effect size of the association between kratom use and substance use disorder was stronger in Malaysia (r = 0.347, 95% CI = [0.209, 0.516], p < 0.001), and with the mean age (β1 = -0.035, 95% CI = [-0.055, -0.014], p = 0.003), and the drug profile of those who were not co-using other drugs (r = 0.347, 95% CI = [0.209, 0.516], p < 0.001).

CONCLUSION

The meta-analysis supports the kratom instrumentalization concept, in that a positive gain from kratom consumption can be achieved without any significant adverse associations with mental health.

Kratom safety and toxicology in the public health context: research needs to better inform regulation

Although kratom use has been part of life for centuries in Southeast Asia, the availability and use of kratom in the United States (US) increased substantially since the early 2000s when there was little information on kratom pharmacology, use patterns, and effects, all critical to guiding regulation and policy. Here we provide a synthesis of research with several hundred English-language papers published in the past 5 years drawing from basic research, epidemiological and surveillance data, and recent clinical research. This review of available literature aims to provide an integrated update regarding our current understanding of kratom's benefits, risks, pharmacology, and epidemiology, which may inform United States-based kratom regulation. Recent surveillance indicates there are likely several million past-year kratom consumers, though estimates vary widely. Even without precise prevalence data, kratom use is no longer a niche, with millions of United States adults using it for myriad reasons. Despite its botanical origins in the coffee tree family and its polypharmacy, kratom is popularly characterized as an opioid with presumed opioid-system-based risks for addiction or overdose. Neuropharmacology, toxicology, and epidemiology studies show that kratom is more accurately characterized as a substance with diverse and complex pharmacology. Taken together the work reviewed here provides a foundation for future scientific studies, as well as a guide for ongoing efforts to regulate kratom. This work also informs much-needed federal oversight, including by the United States Food and Drug Administration. We conclude with recommendations for kratom regulation and research priorities needed to address current policy and knowledge gaps around this increasingly used botanical product.

Isolated Kratom Use Disorder Treated with Extended-Release Buprenorphine Taper

ABSTRACT

This case report highlights a 36-year-old male without history of psychiatric disease, chronic pain, or substance use disorder who developed severe substance use disorder per Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition criteria to kratom. He was successfully treated with sublingual buprenorphine after a 3-year period of intermittent withdrawal management and trials of oral and extended-release injectable naltrexone. After a period of abstinence from kratom, he was tapered from buprenorphine using 2 monthly injections of 100 mg extended-release buprenorphine. His case underscores some of the current uncertainties around kratom use disorder diagnosis and treatment.

An insight review on the neuropharmacological effects, mechanisms of action, pharmacokinetics and toxicity of mitragynine

Mitragynine is one of the main psychoactive alkaloids in Mitragyna speciosa Korth. (kratom). It has opium-like effects by acting on μ-, δ-, and κ-opioid receptors in the brain. The compound also interacts with other receptors, such as adrenergic and serotonergic receptors and neuronal Ca2+ channels in the central nervous system to have its neuropharmacological effects. Mitragynine has the potential to treat diseases related to neurodegeneration such as Alzheimer's disease and Parkinson's disease, as its modulation on the opioid receptors has been reported extensively. This review aimed to provide an up-to-date and critical overview on the neuropharmacological effects, mechanisms of action, pharmacokinetics and safety of mitragynine as a prospective psychotropic agent. Its multiple neuropharmacological effects on the brain include antinociceptive, anti-inflammatory, antidepressant, sedative, stimulant, cognitive, and anxiolytic activities. The potential of mitragynine to manage opioid withdrawal symptoms related to opioid dependence, its pharmacokinetics and toxic effects were also discussed. The interaction of mitragynine with various receptors in the brain produce diverse neuropharmacological effects, which have beneficial properties in neurological disorders. However, further studies need to be carried out on mitragynine to uncover its complex mechanisms of action, pharmacokinetics, pharmacodynamic profiles, addictive potential, and safe dosage to prevent harmful side effects.

Correlations of kratom (Mitragyna speciosa Korth.) tea bag preparations and reported pharmacological effects

ETHNOPHARMACOLOGICAL RELEVANCE

The use of herbal tea infusions is widespread in ethnomedicine throughout the world. One such ethnobotanical is kratom (Mitragyna speciosa Korth., Rubiaceae) which has gained considerable interest as an herbal supplement in recent years in the West beyond its native Southeast Asia. Traditional, kratom leaves are either chewed fresh or made into a tea infusion to treat fatigue, pain, or diarrhea. However, dried kratom leaf powder and hydroalcoholic extracts are more commonly used in Western countries, raising the question of exposure to kratom alkaloids and related effects.

AIM OF THE STUDY

A specific kratom tea bag product was analyzed for mitragynine content using tea infusion preparation and methanolic extraction. Consumers of both the tea bag product and other kratom products completed an online anonymous survey to determine demographics, kratom use patterns, and self-reported beneficial and detrimental effects.

MATERIALS AND METHODS

Kratom tea bag samples were extracted using pH-adjusted water or methanol and analyzed using an established LC-QTOF method. A modified kratom survey was distributed to consumers of the kratom tea bag products and other kratom products over a 14-month period.

RESULTS

Tea infusion extraction of tea bag samples resulted in lower mitragynine levels (0.062-0.131% (w/w)) compared to methanolic extraction (0.485-0.616% (w/w)). Kratom tea bag consumers did report similar, although often milder beneficial effects compared to consumers using other kratom products. Overall self-reported health was better among kratom tea bag consumers whereas improvement of a diagnosed medical condition was less in tea bag consumers compared to those using other kratom products.

CONCLUSIONS

Traditional tea infusions of Mitragyna speciosa dried leaves provide benefits to consumers despite substantially lower mitragynine content. These effects may be less pronounced but indicate that tea infusions provide a potentially safer formulation compared to more concentrated products.

Kratom use disorder: case reports on successful treatment with home induction of buprenorphine-naloxone

BACKGROUND

Kratom has been used for different reasons such as pain, opioid withdrawal, and relaxation. Kratom can cause dependence and overdose, and it's classified under 'drugs of concern' by the US Drug Enforcement Administration. Despite these concerns, kratom is legal in most of the United States and many countries around the world with easy accessibility. Literature searches reveal recommendations to use buprenorphine (or buprenorphine-naloxone), which are medications to treat opioid use disorder, in order to treat patients with kratom use disorder; however, there are no formal guidelines available. Buprenorphine (or buprenorphine-naloxone) induction is recommended to be conducted under observation (i.e. in the clinic) in the United States, but COVID-19 has resulted in shifts toward telehealth.

OBJECTIVES

Describe case series of successful management of kratom use disorder using telehealth followed by unobserved buprenorphine-naloxone home induction and highlight implications for future management, including maintenance dosage and induction method.

METHODS

We present 2 very similar kratom use disorder patients who reported taking 35 g of kratom per day who underwent unobserved buprenorphine-naloxone home induction.

RESULTS

Both were seen via telehealth initially. They reported no adverse effects before, during, or after the unobserved home induction on buprenorphine-naloxone but stabilized on significantly different dosages.

CONCLUSION

Telehealth followed by unobserved buprenorphine-naloxone induction at home may be an alternative to traditional buprenorphine-naloxone induction where treatment accessibility is limited. In addition to daily doses of kratom use, other factors, such as duration of kratom use and individual psychological factors may determine the most comfortable dose of buprenorphine-naloxone.

Correlations of kratom (Mitragyna speciosa Korth.) use behavior and psychiatric conditions from a cross-sectional survey

Kratom (Mitragyna speciosa Korth.) use has increased substantially over the past decade outside of its indigenous regions, especially for the self-treatment of psychiatric conditions. An anonymous, cross-sectional, online survey was completed by 4,945 people who use kratom (PWUK) between July 2019 and July 2020. A total of 2,296 respondents completed an extended survey that included clinical scales for measuring attention deficit hyperactivity disorder (ADHD), posttraumatic stress disorder (PTSD), depressive and anxiety disorders. PWUK and met criteria for ADHD, PTSD, depressive or anxiety disorders were primarily middle-aged (31-50 years), employed, college-level educated, and reported greater concurrent or prior use of kratom with cannabis, cannabidiol, and benzodiazepines. For all psychiatric conditions, PWUK reported decreased depressive and anxious moods than before kratom use. Based on this self-report study, observational and other clinical studies are warranted for kratom. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Effects of mitragynine on viability, proliferation, and migration of C6 rat glioma, SH-SY5Y human neuroblastoma, and HT22 immortalized mouse hippocampal neuron cell lines

Mitragynine (MG) is an indole alkaloid found in the extract of Mitragyna speciosa Korth native to Southeast Asia. Although MG is known for its pain-relieving and psychoactive effects, reports have suggested that it has therapeutic potential against neoplasms and psychiatric disorders. However, no evidence currently exists to support the effect of MG on brain tumors. This study aimed to investigate the antitumor effects of MG in C6 rat glioma and SH-SY5Y human neuroblastoma tumor cell lines compared with those in the non-tumor HT22 mouse hippocampal neuronal cell line. MTT assay for cell viability, clonogenic and wound healing assays for cell migration, Hoechst 33342/propidium iodide staining for nuclear morphology, and cell cycle distribution using flow cytometry were performed. MG at 125.47 μM (50 μg/ml) significantly reduced the viability of all cell lines, and the clonogenicity of C6 glioma cells began decreasing at 75.28 μM (30 μg/ml) of MG. Cell migration was inhibited in C6 and HT22 cells treated with 75.28 μM (30 μg/ml) of MG. Apoptotic nuclear condensation and fragmentation were observed in all cell lines treated with 125.47 μM (50 μg/ml) MG, whereas late-phase apoptotic cells were predominant in the group treated with 250.94 μM (100 μg/ml) of MG. The cell cycle assay results suggest that MG arrested the S phase in the C6 cell line and the G2/M phase in the HT22 cell lines. This study showed that MG induces cell death and cell cycle arrest, disrupting cell migration and reducing the clonogenicity of brain tumor cells.

The dopamine D1 receptor antagonist SCH-23390 blocks the acquisition, but not expression of mitragynine-induced conditioned place preference in rats

Mitragynine (MG) is the primary active constituent of Mitragyna speciosa Korth (kratom), a psychoactive Southeast Asian plant with potential therapeutic use. Numerous studies support roles of dopaminergic system in drug reward. However, the involvement of the dopaminergic system in mediating MG reward and drug-seeking is poorly understood. Using conditioned place preference (CPP) paradigm, the present study aims to evaluate the roles of the dopamine (DA) D1 receptor in the acquisition and expression of MG-induced CPP in rats. The effects of SCH-23390, a selective DA D1 receptor antagonist, on the acquisition of MG-induced CPP were first investigated. Rats were pre-treated systemically with SCH-23390 (0, 0.1 and 0.3 mg/kg, i.p.) prior to MG (10 mg/kg) conditioning sessions. Next, we tested the effects of the DA D1 receptor antagonist on the expression of MG-induced CPP. Furthermore, the effects of a MG-priming dose (5 mg/kg) on the reinstatement of extinguished CPP were tested. The results showed that SCH-23390 dose-dependently suppressed the acquisition of a MG-induced CPP. In contrast, SCH-23390 had no effect on the expression of a MG-induced CPP. The findings of this study suggested a crucial role of the DA D1 receptor in the acquisition, but not the expression of the rewarding effects of MG in a CPP test. Furthermore, blockade of the D1-like receptor during conditioning did not prevent MG priming effects on CPP reinstatement test, suggesting no role for the DA D1 receptor in reinstatement sensitivity.

Cannabinoid mechanisms contribute to the therapeutic efficacy of the kratom alkaloid mitragynine against neuropathic, but not inflammatory pain

AIMS

Mitragynine (MG) is an alkaloid found in Mitragyna speciosa (kratom), a plant used to self-treat symptoms of opioid withdrawal and pain. Kratom products are commonly used in combination with cannabis, with the self-treatment of pain being a primary motivator of use. Both cannabinoids and kratom alkaloids have been characterized to alleviate symptoms in preclinical models of neuropathic pain such as chemotherapy-induced peripheral neuropathy (CIPN). However, the potential involvement of cannabinoid mechanisms in MG's efficacy in a rodent model of CIPN have yet to be explored.

MAIN METHODS

Prevention of oxaliplatin-induced mechanical hypersensitivity and formalin-induced nociception were assessed following intraperitoneal administration of MG and CB1, CB2, or TRPV1 antagonists in wildtype and cannabinoid receptor knockout mice. The effects of oxaliplatin and MG exposure on the spinal cord endocannabinoid lipidome was assessed by HPLC-MS/MS.

KEY FINDINGS

The efficacy of MG on oxaliplatin-induced mechanical hypersensitivity was partially attenuated upon genetic deletion of cannabinoid receptors, and completely blocked upon pharmacological inhibition of CB1, CB2, and TRPV1 channels. This cannabinoid involvement was found to be selective to a model of neuropathic pain, with minimal effects on MG-induced antinociception in a model of formalin-induced pain. Oxaliplatin was found to selectively disrupt the endocannabinoid lipidome in the spinal cord, which was prevented by repeated MG exposure.

SIGNIFICANCE

Our findings suggest that cannabinoid mechanisms contribute to the therapeutic efficacy of the kratom alkaloid MG in a model of CIPN, which may result in increased therapeutic efficacy when co-administered with cannabinoids.

Kratom Alkaloids, Cannabinoids, and Chronic Pain: Basis of Potential Utility and Role in Therapy

Introduction: Chronic neuropathic pain is as a severe detriment to overall quality of life for millions of Americans. Current pharmacological treatment options for chronic neuropathic pain are generally limited in efficacy and may pose serious adverse effects such as risk of abuse, nausea, dizziness, and cardiovascular events. Therefore, many individuals have resorted to methods of pharmacological self-treatment. This narrative review summarizes the existing literature on the utilization of two novel approaches for the treatment of chronic pain, cannabinoid constituents of Cannabis sativa and alkaloid constituents of Mitragyna speciosa (kratom), and speculates on the potential therapeutic benefits of co-administration of these two classes of compounds. Methods: We conducted a narrative review summarizing the primary motivations for use of both kratom and cannabis products based on epidemiological data and summarize the pre-clinical evidence supporting the application of both kratom alkaloids and cannabinoids for the treatment of chronic pain. Data collection was performed using the PubMed electronic database. The following word combinations were used: kratom and cannabis, kratom and pain, cannabis and pain, kratom and chronic pain, and cannabis and chronic pain. Results: Epidemiological evidence reports that the self-treatment of pain is a primary motivator for use of both kratom and cannabinoid products among adult Americans. Further evidence shows that use of cannabinoid products may precede kratom use, and that a subset of individuals concurrently uses both kratom and cannabinoid products. Despite its growing popularity as a form of self-treatment of pain, there remains an immense gap in knowledge of the therapeutic efficacy of kratom alkaloids for chronic pain in comparison to that of cannabis-based products, with only three pre-clinical studies having been conducted to date. Conclusion: There is sufficient epidemiological evidence to suggest that both kratom and cannabis products are used to self-treat pain, and that some individuals actively use both drugs, which may produce potential additive or synergistic therapeutic benefits that have not yet been characterized. Given the lack of pre-clinical investigation into the potential therapeutic benefits of kratom alkaloids against forms of chronic pain, further research is warranted to better understand its application as a treatment alternative.

Kratom use disorder and unfolded protein response: Evaluating their relationship in a case control study

BACKGROUND AND AIMS

Kratom (Mitragyna speciosa Korth.) is widely use worldwide despite its addictive potential. Although psychostimulant use has been linked to occurrence of endoplasmic reticulum (ER) stress, data is lacking on how regular kratom use affects ER stress. This case-control study first determined differences in ER stress sensor protein expression (BiP, sXBP1, ATF4, CHOP, JNK, and p-JNK) between regular kratom users and healthy controls. Second, it evaluated the association between kratom use characteristics, targeted ER stress sensor protein expression, and "kratom use disorder" diagnosed with Diagnostic and Statistical Manual for Mental Disorders 5th Edition (DSM-5) among regular kratom users.

METHODS

In total, 60 regular kratom users and 50 healthy control-group participants were recruited and administered a sociodemographic and clinical characteristics questionnaire. While participants who used kratom were also administered a kratom use characteristics questionnaire. Blood samples were collected from all participants, and targeted ER stress sensor protein expression was determined via Western blot analysis.

RESULTS

The study's findings revealed first that kratom users registered significantly higher protein expression in all targeted ER stress sensors compared to the control group. Second, higher protein expression of CHOP (B = 5.061, standard error [SE] = 2.547, Wald = 3.948, adjusted odds ratio [AOR] = 5.382, 95% confidence interval [CI] = 1.071 to 9.656, p = 0.047) and p-JNK (B = 5.795, SE = 2.635, Wald = 4.544, AOR = 17.025, 95% CI = 1.395 to 24.123, p = 0.017) increased the odds of kratom use disorder occurrence. Kratom use characteristics and other ER stress sensor protein expression were not associated with kratom use disorder.

CONCLUSION

Regular kratom use may induce protracted ER stress, leading to the decompensation of the unfolded protein response to maintain ER homeostasis. This effect may be linked to kratom use disorder occurrence.

Clinical Implications of Kratom (Mitragyna speciosa) Use: a Literature Review

Purpose of Review

This work aims to provide an up-to-date review of the preclinical and clinical scientific literature on the therapeutic value of kratom to better understand the underlying mechanisms related to its use and inform future therapeutic applications.

Recent Findings

A growing number of studies, mainly of cross-sectional nature, describe the widespread use of kratom by individuals to self-treat pain, psychiatric symptoms, and substance use disorders (SUD) outside a controlled clinical setting. Preclinical evidence suggests kratom is effective as an analgesic agent and might decrease the self-administration of other drugs. A randomized controlled trial has further supported kratom's therapeutic value as an analgesic. Investigations in nonclinical samples of long-term kratom users also indicate its therapeutic benefit in managing SUD symptoms (e.g., craving) and long-term or acute symptoms (e.g., withdrawal) for alcohol, opioids, and other illicit drugs. However, episodes of kratom-related intoxications have also been reported, often due to the adulteration and the contamination of kratom products mainly sold online or mixed toxicities when consumed outside clinical and traditional settings.

Summary

Evidence on the clinical implications of kratom use is still limited and uncertain, with kratom research constantly evolving. Therefore, further randomized trials are needed.

Kratom's Emergence and Persistence Within the US Polydrug Epidemic

Purpose of Review

Use of "kratom" products, derived from the bioactive botanical Mitragyna speciosa have increased amidst US polydrug use epidemics. Kratom alkaloids interact with opioid, serotonergic, adrenergic, and other receptors and regular users have described experiencing a wide range of effects. Some with polydrug use histories have reported using kratom as a substitute for other drugs or to nonmedically self-manage substance use disorder (SUD) symptoms. Data describing this remain scare and come from self-report. We review this literature describing kratom use as a drug substitute, or as a nonmedical "self-treatment" for attenuating dependence or SUD symptoms.

Recent Findings

Kratom products have been documented as being used as a licit and illicit opioid substitute. Use to reduce alcohol or stimulant consumption is less well documented. Although prior and current polydrug use appear common among a some kratom users, it is unclear if co-use is contemporaneous or concomitant. Temporal order of use initiation is typically undocumented. Use for energy and recreation are also increasingly reported.

Summary

Data on kratom consumption come primarily from self-report with significant limitations. Until controlled human laboratory studies have been conducted, we can presently only describe what is known about human kratom use based on self-report. Such data describe real-world kratom use, leaving unaddressed human abuse liability or therapeutic potential of kratom alkaloids. Clinicians should be mindful of use motivations among people with SUD histories, sensitively assessing use. The paucity of data highlights the urgent need to increase funding and research for understanding kratom's effects in humans.

Evaluating health information provided to kratom consumers by good manufacturing practice-qualified vendors

BACKGROUND

"Kratom" commonly refers to the botanical Mitragyna speciosa, native to Southeast Asia, which is increasingly used globally for its unique pharmacological effects. Motives for using the whole plant material or kratom-derived products include self-management of pain, mental health disorders, symptoms related to substance use disorders, and/or to increase energy. In the United States, kratom products have varying alkaloid content, potencies, and marketing profiles. There is little regulatory oversight over kratom, as it is currently not approved as a dietary supplement by the Food and Drug Administration. This results in substantial variability in labeling of kratom products and the product information provided to consumers.

METHODS

In January 2023, we evaluated the American Kratom Association's Good Manufacturing Practices (GMP) qualified vendors' websites (n = 42) using the well-established and validated DISCERN instrument to examine the quality of health information provided to consumers. DISCERN contains 15 five-point Likert-scale questions on specific criteria, with the highest possible score being 75, indicating that all the DISCERN criteria have been fulfilled by the website (i.e., the highest quality information is provided to consumers).

RESULTS

The mean DISCERN score for all evaluated online kratom vendors was 32.72 (SD = 6.69; score range 18.00-43.76). Overall, vendors scored higher on DISCERN questions assessing the website's reliability, as vendors typically provided clear information for consumers about product availability, purchasing, shipping, etc. On average, vendors scored poorly on the DISCERN section pertaining to the quality of the health information provided. Information on kratom's potential risks and benefits was particularly insufficient.

CONCLUSIONS

Consumers require high quality information in order to make informed decisions concerning use, which entails disclosure of known risks and potential benefits. The online kratom vendors evaluated in this study should consider enhancing the quality of health information provided, especially information regarding kratom's risks and benefits. Further, consumers should be made aware of current knowledge gaps related to kratom's effects. Clinicians must also be aware of the lack of evidence-based information available to their patients who use kratom or are interested in using kratom products, in order to facilitate educational discussions with them.

Directed Biosynthesis of Mitragynine Stereoisomers

Mitragyna speciosa ("kratom") is used as a natural remedy for pain and management of opioid dependence. The pharmacological properties of kratom have been linked to a complex mixture of monoterpene indole alkaloids, most notably mitragynine. Here, we report the central biosynthetic steps responsible for the scaffold formation of mitragynine and related corynanthe-type alkaloids. We illuminate the mechanistic basis by which the key stereogenic center of this scaffold is formed. These discoveries were leveraged for the enzymatic production of mitragynine, the C-20 epimer speciogynine, and fluorinated analogues.

An evaluation of adverse drug reactions and outcomes attributed to kratom in the US Food and Drug Administration Adverse Event Reporting System from January 2004 through September 2021

Kratom is a widely used Asian botanical that has gained popularity in the United States due to a perception that it can treat pain, anxiety, and opioid withdrawal symptoms. The American Kratom Association estimates 10-16 million people use kratom. Kratom-associated adverse drug reactions (ADRs) continue to be reported and raise concerns about the safety profile of kratom. However, studies are lacking that describe the overall pattern of kratom-associated adverse events and quantify the association between kratom and adverse events. ADRs reported to the US Food and Drug Administration Adverse Event Reporting System from January 2004 through September 2021 were used to address these knowledge gaps. Descriptive analysis was conducted to analyze kratom-related adverse reactions. Conservative pharmacovigilance signals based on observed-to-expected ratios with shrinkage were estimated by comparing kratom to all other natural products and drugs. Based on 489 deduplicated kratom-related ADR reports, users were young (mean age 35.5 years), and more often male (67.5%) than female patients (23.5%). Cases were predominantly reported since 2018 (94.2%). Fifty-two disproportionate reporting signals in 17 system-organ-class categories were generated. The observed/reported number of kratom-related accidental death reports was 63-fold greater than expected. There were eight strong signals related to addiction or drug withdrawal. An excess proportion of ADR reports were about kratom-related drug complaints, toxicity to various agents, and seizures. Although further research is needed to assess the safety of kratom, clinicians and consumers should be aware that real-world evidence points to potential safety threats.

Buprenorphine-Naloxone in the Setting of Kratom Withdrawal, Opioid Use Disorder, and Stage IV Lung Adenocarcinoma

Management of cancer-associated pain warrants consideration of many factors, including characterization and etiology of the pain, socioeconomic factors, medication tolerance, and substance use history. Kratom (Mitragyna speciosa) is an herbal substance with stimulant and analgesic properties that is becoming a popular drug in the United States. In this report, we present a patient with a history of opioid use disorder (OUD) who had been using high doses of kratom to alleviate progressive chest pain and dyspnea secondary to newly diagnosed stage IV lung adenocarcinoma. He underwent kratom withdrawal shortly after his index admission and was reluctant to continue full opioid agonists given his history of OUD and complex living situation. His kratom withdrawal and cancer-associated symptoms were successfully managed with buprenorphine-naloxone. Providers should obtain a careful history of novel substance use such as kratom. Furthermore, buprenorphine-naloxone is a safe and effective option to simultaneously manage kratom withdrawal and cancer-associated pain.

The association between E-cigarette use and Kratom use among US adults

Kratom, an herbal substance with stimulant and opioid-like effects commonly used in capsules or powder to be ingested or brewed as a tea, has been gaining popularity in the United States (US). US e-cigarette use (i.e., vaping) has exponentially increased in recent years. Given the potential risks of kratom (e.g., poisonings) and the increasing prevalence of e-cigarette use, understanding the association between them is important to inform prevention strategies and regulatory policies. We harnessed data from the 2020 National Survey on Drug Use and Health (NSDUH; n = 27,170) to examine past-year kratom use by past-year e-cigarette use among adults. We ran a logistic regression model on kratom use by e-cigarette use adjusting for associated factors with substance use. Among all respondents, the estimated prevalence of past-year kratom use was 0.9% and an estimated 9.7% reported past-year e-cigarette use. Our multivariable model found those with e-cigarette use (vs. not) had 4.80 higher odds of using kratom in the past year (aOR = 4.80; 95% CI = 2.62, 8.80). These findings might help inform the need for continuing education for physicians and healthcare providers related to practice in managing patients with kratom use, future studies for regulatory policies on e-cigarettes (e.g., e-liquids), or other FDA policies related to kratom.

A Case of Severe Kratom Addiction Contributing to a Suicide Attempt

Kratom is a plant product native to Southeast Asia that is surging in popularity in the United States as consumers look for natural remedies for ailments like chronic pain, anxiety, and even opioid addiction. Kratom's risks are largely unknown, and the market is poorly regulated. Americans typically get advice from online forums and purchase powder formulations from tobacco shops or obscure websites. These risks are highlighted in this case of a 38-year-old woman with a history of major depressive disorder and opioid use disorder who switched from Suboxone to kratom and became addicted, eventually consuming large quantities per day. Amplified by other stressors, she reached a breaking point and overdosed on her regular medications for depression. At the psychiatric hospital, she exhibited classic kratom withdrawal symptoms, including vague abdominal pain and restlessness. After eight days of treatment, her symptoms eventually abated, and she was discharged on Suboxone.

Inhibition of α-Glucosidase and Pancreatic Lipase Properties of Mitragyna speciosa (Korth.) Havil. (Kratom) Leaves

Kratom (Mitragyna speciosa (Korth.) Havil.) has been used to reduce blood sugar and lipid profiles in traditional medicine, and mitragynine is a major constituent in kratom leaves. Previous data on the blood sugar and lipid-altering effects of kratom are limited. In this study, phytochemical analyses of mitragynine, 7-hydroxymitragynine, quercetin, and rutin were performed in kratom extracts. The effects on α-glucosidase and pancreatic lipase activities were investigated in kratom extracts and mitragynine. The LC-MS/MS analysis showed that the mitragynine, quercetin, and rutin contents from kratom extracts were different. The ethanol extract exhibited the highest total phenolic content (TPC), total flavonoid content (TFC), and total alkaloid content (TAC). Additionally, compared to methanol and aqueous extracts, the ethanol extract showed the strongest inhibition activity against α-glucosidase and pancreatic lipase. Compared with the anti-diabetic agent acarbose, mitragynine showed the most potent α-glucosidase inhibition, with less potent activity of pancreatic lipase inhibition. Analysis of α-glucosidase and pancreatic lipase kinetics revealed that mitragynine inhibited noncompetitive and competitive effects, respectively. Combining mitragynine with acarbose resulted in a synergistic interaction with α-glucosidase inhibition. These results have established the potential of mitragynine from kratom as a herbal supplement for the treatment and prevention of diabetes mellitus.

Kratom alkaloid mitragynine: Inhibition of chemotherapy-induced peripheral neuropathy in mice is dependent on sex and active adrenergic and opioid receptors

Mitragynine (MG) is an alkaloid found in Mitragyna speciosa (kratom) that is used as an herbal remedy for pain relief and opioid withdrawal. MG acts at μ-opioid and α-adrenergic receptors in vitro, but the physiological relevance of this activity in the context of neuropathic pain remains unknown. The purpose of the present study was to characterize the effects of MG in a mouse model of chemotherapy-induced peripheral neuropathy (CIPN), and to investigate the potential impact of sex on MG's therapeutic efficacy. Inhibition of oxaliplatin-induced mechanical hypersensitivity was measured following intraperitoneal administration of MG. Both male and female C57BL/6J mice were used to characterize potential sex-differences in MG's therapeutic efficacy. Pharmacological mechanisms of MG were characterized through pretreatment with the opioid and adrenergic antagonists naltrexone, prazosin, yohimbine, and propranolol (1, 2.5, 5 mg/kg). Oxaliplatin produced significant mechanical allodynia of equal magnitude in both male and females, which was dose-dependently attenuated by repeated MG exposure. MG was more potent in males vs females, and the highest dose of MG (10 mg/kg) exhibited greater anti-allodynic efficacy in males. Mechanistically, activity at µ-opioid, α₁- and α₂-adrenergic receptors, but not β-adrenergic receptors contributed to the effects of MG against oxaliplatin-induced mechanical hypersensitivity. Repeated MG exposure significantly attenuated oxaliplatin-induced mechanical hypersensitivity with greater potency and efficacy in males, which has crucial implications in the context of individualized pain management. The opioid and adrenergic components of MG indicate that it shares pharmacological properties with clinical neuropathic pain treatments.

Public Health Implications and Possible Sources of Lead (Pb) as a Contaminant of Poorly Regulated Kratom Products in the United States

Kratom (Mitragyna speciosa) is a tropical tree that is indigenous to Southeast Asia. Kratom leaf products have been used in traditional folk medicine for their unique combination of stimulant and opioid-like effects. Kratom is being increasingly used in the West for its reputed benefits in the treatment of pain, depression, and opioid use disorder (OUD). Recent studies from the United States Food and Drug Administration (FDA, Silver Spring, MD, USA) and our laboratory have shown that many kratom products being sold in the United States are contaminated with potentially hazardous levels of lead (Pb). In this commentary, we discuss the public health implications of the presence of Pb in kratom products, particularly as they relate to the predicted levels of Pb exposure among kratom users. We also considered the specific toxic effects of Pb and how they might relate to the known physiologic and toxicologic effects of kratom. Finally, we consider the possible sources of Pb in kratom products and suggest several areas for research on this issue.

Need for clarity and context in case reports on kratom use, assessment, and intervention

This Letter to the Editor is a response to Broyan and colleagues who recently published a Case Report presenting data on 28 patients in the United States who identified kratom as their primary substance of use and who were subsequently induced on buprenorphine/naloxone for a reported diagnosis of kratom use disorder. We applaud the authors for helping to advance the science on kratom and recognize the difficulties in conducting kratom-related clinical assessment and research. However, a number of inconsistences and generalizations were identified in this Case Report, which also lacked some critical context. Importantly, such inconsistencies and generalizations can be observed throughout kratom-specific case reports. We feel this is now an important opportunity to highlight these issues that are present in the Broyan and colleagues Case report but emphasize that they are not unique to it. We do this with the hope that by acknowledging these issues it can help inform editors, clinicians, and researchers who may not be familiar with kratom and, as a result of this unfamiliarity, may inadvertently present findings in a manner that could confuse readers and even misinform clinical researchers and practitioners.

Respiratory effects of oral mitragynine and oxycodone in a rodent model

RATIONALE

Kratom derives from Mitragyna speciosa (Korth.), a tropical tree in the genus Mitragyna (Rubiaceae) that also includes the coffee tree. Kratom leaf powders, tea-like decoctions, and commercial extracts are taken orally, primarily for health and well-being by millions of people globally. Others take kratom to eliminate opioid use for analgesia and manage opioid withdrawal and use disorder. There is debate over the possible respiratory depressant overdose risk of the primary active alkaloid, mitragynine, a partial μ-opioid receptor agonist, that does not signal through ß-arrestin, the primary opioid respiratory depressant pathway.

OBJECTIVES

Compare the respiratory effects of oral mitragynine to oral oxycodone in rats with the study design previously published by US Food and Drug Administration (FDA) scientists for evaluating the respiratory effects of opioids (Xu et al., Toxicol Rep 7:188-197, 2020).

METHODS

Blood gases, observable signs, and mitragynine pharmacokinetics were assessed for 12 h after 20, 40, 80, 240, and 400 mg/kg oral mitragynine isolate and 6.75, 60, and 150 mg/kg oral oxycodone hydrochloride.

FINDINGS

Oxycodone administration produced significant dose-related respiratory depressant effects and pronounced sedation with one death each at 60 and 150 mg/kg. Mitragynine did not yield significant dose-related respiratory depressant or life-threatening effects. Sedative-like effects, milder than produced by oxycodone, were evident at the highest mitragynine dose. Maximum oxycodone and mitragynine plasma concentrations were dose related.

CONCLUSIONS

Consistent with mitragynine's pharmacology that includes partial µ-opioid receptor agonism with little recruitment of the respiratory depressant activating β-arrestin pathway, mitragynine produced no evidence of respiratory depression at doses many times higher than known to be taken by humans.