Experiences of Kratom Users: A Qualitative Analysis

Pharmacologic and clinical assessment of kratom: An update

PURPOSE

This article presents updated information on kratom (Mitragyna speciosa), a natural opioid with stimulant properties that is currently sold in the United States without a prescription.

SUMMARY

Kratom exerts opioid and alpha-2 agonistic effects, as well as anti-inflammatory and mild stimulant effects. Respiratory depression has not been commonly reported, but kratom does cause a host of adverse effects. While kratom may have a role in patients who are in chronic pain or dependent on opioid painkillers or heroin, this needs to be established in clinical trials. Kratom may have drug interactions as both a cytochrome P-450 system substrate and inhibitor. Kratom does not appear in normal drug screens and, especially when ingested with other substances of abuse, may not be recognized as an agent of harm. There are numerous cases of death in kratom users, but many involved polypharmaceutical ingestions. There are assessments where people have been unable to stop using kratom therapy and withdrawal signs/symptoms occurred in patients or their newborn babies after kratom cessation. Both banning and failure to ban kratom places people at risk; a middle-ground alternative, placing it behind the pharmacy counter, might be useful.

CONCLUSION

Kratom has a unique pharmacologic profile that might offer advantages over other opioids, but its high abuse liability, potential for drug interactions and adverse events, and inadequate research into the balance of benefits to harm are concerning. There is mounting information on the adverse events associated with kratom use and potential treatments that can be useful to clinicians.

Kratom and Future Treatment for the Opioid Addiction and Chronic Pain: Periculo Beneficium?

Kratom (Mitragyna speciosa), a naturally existing plant found in South-East Asia, is traditionally used as a herb to help elevate a person's energy and also to treat numerous medical ailments. Other than the analgesic property, kratom has been used as an agent to overcome opioid withdrawal as it contains natural alkaloids, i.e. mitragynine, 7-hydroxymitragynine, and MGM-9, which has agonist affinity on the opioid receptors, including mu (µ) and kappa (κ). The role of neural reward pathways linked to µ-opioid receptors and both dopaminergic and gamma-Aminobutyric acid (GABA)-ergic interneurons that express µ-opioid receptors were deliberated. However, kratom has been reported to be abused together with other illicit substances with high risk of potential addiction. There are also anecdotes of adverse effects and toxicity of kratom, i.e. tremor, fatigue, seizure, and death. Different countries have distinctive regulation and policy on the plantation and use of this plant when most of the countries banned the use of it because of its addiction problems and side effects. The aim of this review is to highlight on the potential use of kratom, unique 'herbs" as a substitution therapy for chronic pain and opioid addiction, based on the neurobiological perspective of pain and the underlying mechanism of actions of drug addiction.

Kratom (Mitragyna speciosa): User demographics, use patterns, and implications for the opioid epidemic

BACKGROUND

Kratom, a Southeast Asian plant with opioid-receptor mediated effects, has emerged as a potential substance of abuse, with limited data on its use and effects. This study characterized kratom user demographics, use patterns, and perceived drug effects.

METHODS

A cross-sectional, anonymous online survey was conducted between January and December 2017.

RESULTS

2,798 kratom users - mean age 40 (SD = 12); predominantly White (90 %), female (61 %), and located in the US (97 %) - completed the survey. Kratom was primarily taken orally in doses of 1-3 g (49 %), with daily use (59 %) being most common. Kratom was used for pain (91 %), anxiety (67 %), and depression (65 %), with high ratings of effectiveness. 1,144 (41 %) used kratom to stop or reduce prescription or illicit opioid use, citing decreased opioid withdrawal and craving related to kratom use, with 411 reporting >1-year continuous abstinence from opioids attributed to kratom use. Roughly one-third of respondents reported adverse effects of kratom, largely rated as mild in severity and lasting ≤24 h. Seventeen participants (0.6 %) sought treatment for adverse effects. Fifty-six individuals (2 %) met DSM-5 criteria for a past-year moderate or severe kratom-related substance use disorder (SUD). When asked how troubled they felt regarding their kratom use, the mean (SD) rating was 3.2 (9.8) on a scale from 0 to 100.

CONCLUSION

Kratom is used among White, middle-aged Americans for symptoms of pain, anxiety, depression, and opioid withdrawal. Although regular use was typical, kratom-related SUD and serious adverse effects were uncommon. Additional research on kratom epidemiology and pharmacology is imperative in light of the present opioid epidemic.

Patterns and reasons for kratom (Mitragyna speciosa) use among current and former opioid poly-drug users

ETHNOPHARMACOLOGICAL RELEVANCE

Kratom (Mitragyna speciosa) is a native medicinal plant of Southeast Asia widely reported to be used to reduce opioid dependence and mitigate withdrawal symptoms. There is also evidence to suggest that opioid poly-drug users were using kratom to abstain from opioids.

AIM OF THE STUDY

To determine the patterns and reasons for kratom use among current and former opioid poly-drug users in Malaysia.

MATERIALS AND METHODS

A total of 204 opioid poly-drug users (142 current users vs. 62 former users) with current kratom use history were enrolled into this cross-sectional study. A validated UPLC-MS/MS method was used to evaluate the alkaloid content of a kratom street sample.

RESULTS

Results from Chi-square analysis showed that there were no significant differences in demographic characteristics between current and former opioid poly-drug users except with respect to marital status. Current users had higher odds of being single (OR: 2.2: 95%CI: 1.21-4.11; p < 0.009). Similarly, there were no significant differences in the duration (OR: 1.1: 0.62-2.03; p < 0.708), daily quantity (OR: 1.5: 0.85-2.82; p < 0.154) or frequency of kratom use between current and former opioid poly-drug users (OR: 1.1: 0.62-2.06; p < 0.680). While both current and former opioid users reported using kratom to ameliorate opioid withdrawal, current users had significantly higher likelihood of using kratom for that purpose (OR: 5.4: 95%CI: 2.81-10.18; p < 0.0001). In contrast, former opioid users were more likely to be using kratom for its euphoric (mood elevating) effects (OR: 1.9: 95%CI: 1.04-3.50; p < 0.035). Results from the UPLC-MS/MS analysis indicated the major alkaloids present in the representative kratom street sample (of approximately 300 mL of brewed kratom) were mitragynine, followed by paynantheine, speciociliatine and speciogynine, as well as low levels of 7-hydroxymitragynine.

CONCLUSIONS

Both current and former opioid poly-drug users regularly used kratom (three glasses or about 900 mL daily or the equivalent of 170.19 mg of mitragynine) to overcome opioid poly-drug use problems.

Assessing physiological dependence and withdrawal potential of mitragynine using schedule-controlled behaviour in rats

RATIONALE

Kratom is proposed to exhibit therapeutic potential as an opium substitute, but little is known about its dependence-producing profile, particularly of its main psychoactive compound, mitragynine (MG).

OBJECTIVES

This study examined the dependence-producing effects of MG using operant-scheduled behaviour in rats and investigated the potential therapeutic effect of MG by comparing effects to buprenorphine in morphine-dependent rats using the same schedule-controlled behavioural task.

METHODS

The effects of acutely administered MG and morphine were determined in rats trained to respond under fixed-ratio (FR) 10 schedule of food reinforcement. Next, the rats were administered MG and morphine twice daily for 14 consecutive days to determine if physiological dependence would develop by examining cessation of drug treatment and following antagonist-precipitated withdrawal. The study then examined the effects of MG substitution to suppress naloxone-precipitated morphine withdrawal effects on scheduled responding.

RESULTS

Acute doses of MG did not produce dose-related decreases on FR schedules of responding compared to morphine. Unlike morphine, MG-treated rats showed no suppression of response rates following cessation of MG treatment. However, withdrawal effects were evident for MG after precipitation by either naloxone or SR141716A (rimonabant), similar to morphine-treated rats. MG in higher doses (10 and 30 mg/kg) attenuated the naloxone-precipitated morphine withdrawal effects while smaller doses of buprenorphine (0.3 and 1.0 mg/kg) were necessary to alleviate these effects.

CONCLUSION

The findings suggest that MG does not induce physiological dependence but can alleviate the physical symptoms associated with morphine withdrawal which represent the desired characteristics of novel pharmacotherapeutic interventions for managing opioid use disorder (OUD).

Exploration of cytochrome P450 inhibition mediated drug-drug interaction potential of kratom alkaloids

In vitro cytochrome P450 inhibition of major kratom alkaloids: mitragynine (MTG), speciogynine (SPG), speciocilliatine (SPC), corynantheidine (COR), 7-hydroxymitragynine (7HMG) and paynantheine (PAY) was evaluated using human liver microsomes (HLMs) to understand their drug-drug interaction potential. CYP450 isoform-specific substrates of CYP1A2, 2C8, 2C9, 2C19, 2D6, and 3A4/5 were incubated in HLMs with or without alkaloids. Preliminary CYP450 inhibition (IC50) data were generated for each of these isoforms. In addition, the type of inhibition and estimation of the inhibition constants (Ki) of MTG and COR were determined. Among the tested alkaloids, MTG and COR were potent inhibitors of CYP2D6 (IC50, 2.2 and 4.2 μM, respectively). Both MTG and COR exhibited competitive inhibition of CYP2D6 activity and the Ki were found to be 1.1 and 2.8 μM, respectively. SPG and PAY showed moderate inhibition of CYP2D6 activity. Additionally, moderate inhibitory effects by SPC, MTG, and SPG were observed on CYP2C19 activity. Interestingly, inhibition of only midazolam hydroxylase CYP3A4/5 activity by COR, PAY, and MTG was observed while no inhibitory effect was observed when testosterone was used as a probe substrate. In conclusion, MTG and COR may lead to clinically significant adverse drug interactions upon coadministration of drugs that are substantially metabolized by CYP2D6.

The influence of context on ayahuasca experiences: An analysis of experience reports

Background and aims

Ayahuasca is a psychedelic decoction prepared from two (or more) plants containing monoamine oxidase inhibitors, N, N-dimethyltryptamine, and other chemicals. Ayahuasca has apparently been used for centuries in the Amazon basin of South America, and in recent years has increasingly been used internationally in diverse contexts. This study aims to elucidate differences between cross-cultural ceremonial and psychonautic contexts of ayahuasca use.

Methods

This study systematically examines subjective differences across contexts for contemporary ayahuasca-drinking practices. User reports of ayahuasca experiences were subjected to textual analysis to compare use in cross-culturalceremonial contexts that attempt to include elements of traditional Amazonian practices, with psychonautic use that does not formally integrate traditional ceremonial aspects. The experience reports were collected from an online database.

Results

The use of ayahuasca in a cross-cultural ceremonial context is associated with prominence of affective and motivational features, whereas psychonautic use was associated with an emphasis on cognitive processes.

Conclusions

The beneficial effects of ayahuasca may operate via affective processing and integration and as such, cross-cultural ceremonial use may have advantages relative to psychonautic use. Findings are considered in light of the importance of context on experiences with ayahuasca and other psychedelic substances.

Adverse Events Due to Insomnia Drugs Reported in a Regulatory Database and Online Patient Reviews: Comparative Study

BACKGROUND

Patient online drug reviews are a resource for other patients seeking information about the practical benefits and drawbacks of drug therapies. Patient reviews may also serve as a source of postmarketing safety data that are more user-friendly than regulatory databases. However, the reliability of online reviews has been questioned, because they do not undergo professional review and lack means of verification.

OBJECTIVE

We evaluated online reviews of hypnotic medications, because they are commonly used and their therapeutic efficacy is particularly amenable to patient self-evaluation. Our primary objective was to compare the types and frequencies of adverse events reported to the Food and Drug Administration Adverse Event Reporting System (FAERS) with analogous information in patient reviews on the consumer health website Drugs.com. The secondary objectives were to describe patient reports of efficacy and adverse events and assess the influence of medication cost, effectiveness, and adverse events on user ratings of hypnotic medications.

METHODS

Patient ratings and narratives were retrieved from 1407 reviews on Drugs.com between February 2007 and March 2018 for eszopiclone, ramelteon, suvorexant, zaleplon, and zolpidem. Reviews were coded to preferred terms in the Medical Dictionary for Regulatory Activities. These reviews were compared to 5916 cases in the FAERS database from January 2015 to September 2017.

RESULTS

Similar adverse events were reported to both Drugs.com and FAERS. Both resources identified a lack of efficacy as a common complaint for all five drugs. Both resources revealed that amnesia commonly occurs with eszopiclone, zaleplon, and zolpidem, while nightmares commonly occur with suvorexant. Compared to FAERS, online reviews of zolpidem reported a much higher frequency of amnesia and partial sleep activities. User ratings were highest for zolpidem and lowest for suvorexant. Statistical analyses showed that patient ratings are influenced by considerations of efficacy and adverse events, while drug cost is unimportant.

CONCLUSIONS

For hypnotic medications, online patient reviews and FAERS emphasized similar adverse events. Online reviewers rated drugs based on perception of efficacy and adverse events. We conclude that online patient reviews of hypnotics are a valid source that can supplement traditional adverse event reporting systems.

Treatment of Kratom Dependence With Buprenorphine-Naloxone Maintenance

INTRODUCTION

Use of the unregulated herbal supplement kratom is on the rise in the United States. We present a case series of 2 patients who developed kratom dependence and withdrawal who were successfully transitioned to buprenorphine-naloxone maintenance.

CASE SUMMARY

Two patients using kratom to self-treat chronic pain after prescription opioids were discontinued presenting to our clinic with evidence of kratom dependence and withdrawal. On examination, both patients showed signs of mild opioid withdrawal. Both patients were successfully transitioned to buprenorphine-naloxone maintenance via home initiation with control of both their opioid withdrawal and chronic pain.

CONCLUSIONS

Kratom use is on the rise and with increasing evidence of developing opioid-type dependence due to chronic kratom use. This case series shows that buprenorphine can be used to treat kratom dependence and underlying chronic pain that drives it use.

Self-Report Data on Regular Consumption of Illicit Drugs and HIV Risk Behaviors after Kratom (Mitragyna Speciosa korth.) Initiation among Illicit Drug Users in Malaysia

This study sought to determine the relationship between kratom (Mitragyna speciosa) initiation and regular consumption of illicit drugs and HIV risk behaviors in a cohort of illicit drug users in Malaysia. 260 illicit drug users with current kratom use were recruited through convenience sampling for this cross-sectional study. All were male, with the majority being Malays (95%, n = 246/260). Results suggest that kratom initiation was associated with significant decrease in the regular use of heroin (odds ratio (OR) = 0.50, 95% confidence interval (CI): 0.40- 0.72; p = .0001), methamphetamine (OR = 0.23, CI: 0.16- 0.35; p < .0001), and amphetamine (OR = 0.17, CI: 0.09- 0.34; p < .0001). Kratom initiation was also associated with reduction in regular HIV risk behaviors such as having sex with sex workers (OR = 0.20, CI: 0.12-0.32; p < .0001), using drugs before sexual intercourse (OR = 0.20, CI: 0.13- 0.31; p < .0001), injecting behaviors (OR = 0.10, CI: 0.04- 0.25; p < .0001), sharing of injection equipment (OR = 0.13, CI: 0.04- 0.43; p < .0001), and injecting with other injection drug users (IDUs) (OR = 0.07, CI: 0.02- 0.24; p < .0001).

Pharmacokinetics and pharmacodynamics of mitragynine, the principle alkaloid of Mitragyna speciosa: present knowledge and future directions in perspective of pain

Mitragyna speciosa, commonly known as Ketum or Biak in Malaysia and Kratom in Thailand, is a native plant to Southeast Asia and has various pharmacological benefits. Mitragynine (MG) is the principal alkaloid found in the leaves of Mitragyna speciosa and has been reported to be responsible for the plant's therapeutic actions. Traditionally, local communities use Kratom preparations for relief from different types of pain. The potential analgesic effects of MG using rodent models have been reported in literatures. We have reviewed the published analgesic and pharmacokinetic studies and all of these findings showed the routes of drug administration, doses employed, and type of vehicles used to solubilize the drug, varied considerably; hence this posted difficulties in predicting the drug's pharmacokinetic-response relationship. A rational approach is warranted for accurate prediction of dose-response relationship; as this is essential for the development of MG as an alternative medicinal drug for pain management. PKPD modeling would serve as a better method to understand the dose-response relationship in future MG preclinical and clinical studies.

Kratom from Head to Toe—Case Reviews of Adverse Events and Toxicities

Purpose of Review

This review describes case reports for patients with kratom-associated adverse events in order to assist clinicians with patient management. A stepwise approach is proposed for assessing active kratom users as well as considerations for the management of toxicities or withdrawal.

Recent Findings

Multiple in vitro and in vivo studies illustrate the pharmacologic and toxicologic effects of kratom extract. No randomized controlled trials in humans exist that assess the safety and efficacy of the substance. Cross-sectional surveys from active users and reports from poison control centers have shown acute and chronic physiological and psychological adverse events.

Summary

Reports of adverse effects associated with kratom use have demonstrated hypothyroidism, hypogonadism, hepatitis, acute respiratory distress syndrome, posterior reversible encephalopathy syndrome, seizure, and coma. Overdose toxidrome leads to respiratory failure, cardiac arrest, and fatalities. Adult and neonatal withdrawal symptoms have also occurred. Clinicians should be aware of the risks and benefits of kratom use.

Kratom as a substitute for opioids: Results from an online survey

BACKGROUND

Kratom is a South Eastern Asian tree whose leaves are used to make tea-like brews or swallowed in powdered form for various health and well-being reasons including to relieve pain and opioid withdrawal. It is important to learn more about the potential public health impact of kratom in the context of the opioid epidemic.

METHODS

An anonymous online survey of kratom users (2867 current users and 157 former users) was conducted in September 2017 through the American Kratom Association and associated social media sites.

RESULTS

Kratom was used primarily to relieve pain (endorsed by 48% of respondents), for anxiety, PTSD, or depression (22%), to increase energy or focus (10%) and to help cut down on opioid use and/or relieve withdrawal (10%). Over 90% of respondents who used it in place of opioids indicated that it was helpful to relieve pain, reduce opioid use, and relieve withdrawal. The reported incidence of bad adverse reactions was 13%, and reactions were overwhelmingly mild and self-managed.

CONCLUSIONS

Respondents reported using kratom for conditions which often require use of opioids, including pain and reduction of opioid use. The high self-reported efficacy and low incidence of adverse reactions associated with kratom use suggest that it may provide a potential alternative to opioids for some persons even though it has not been evaluated in multi-center clinical trials or approved for any therapeutic purpose. Further study of kratom, including systematic characterization of its safety and efficacy for various conditions is warranted.

Distinct kratom user populations across the United States: A regional analysis based on an online survey

OBJECTIVE

Kratom preparations have raised concerns of public health and safety in the United States. This paper analyzed the patterns and predictors of kratom use by four U.S. regions according to the U.S. Census.

METHOD

An anonymous cross-sectional online survey yielded 8,049 valid responses. The data were categorised by regions (Northeast, South, Midwest, and West) and analyzed for the following predictors: age, gender, marital status, ethnicity, employment status, insurance coverage, education, and household income.

RESULTS

After adjusting for state population, the survey response rates were highest from Oregon, Idaho, and Florida. Kratom use was significantly lower for both prescription drug dependency and acute or chronic pain in the Northeast region than the rest of the country. Multiple logistic regression models found that gender, employment, and education were significant on the regional level. Higher education was associated with lower kratom use for an illicit drug dependency (p = .002) independent of region whereas men were less likely to use kratom for acute or chronic pain in the Northeast (p < .001) but more likely in the Midwest (p = .041).

CONCLUSIONS

The regional pattern of kratom use differed from opioid use data in both demographics and trend direction warranting further investigation.

The effects of mitragynine and morphine on schedule-controlled responding and antinociception in rats

RATIONALE

Mitragyna speciosa (kratom) may hold promise as both an analgesic and treatment for opioid use disorder. Mitragynine, its primary alkaloid constituent, is an opioid receptor ligand. However, the extent to which the in vivo effects of mitragynine are mediated by opioid receptors, or whether mitragynine interacts with other opioid agonists, is not fully established.

OBJECTIVES

The effects of mitragynine and the prototypical opioid agonist morphine were compared for their capacity to decrease operant responding for food delivery, and to increase response latency to a thermal stimulus.

METHODS

Male and female Sprague-Dawley rats responded under a multiple cycle fixed ratio 10 schedule of food delivery and were tested on a hot plate (52 °C) immediately after each cycle. Morphine and mitragynine were administered alone, in combination with each other, and in combination with the opioid antagonist naltrexone.

RESULTS

Morphine and mitragynine dose-dependently decreased schedule-controlled responding; the ED50 values were 7.3 and 31.5 mg/kg, respectively. Both drugs increased thermal antinociception; the ED50 value for morphine was 18.3. Further, doses of naltrexone that antagonized morphine did not antagonize mitragynine. Mitragynine (17.8 mg/kg) did not alter the rate-decreasing or antinociceptive effects of morphine.

CONCLUSIONS

The antinociceptive effects of mitragynine and morphine occur at doses larger than those that disrupt learned behavior. Opioid receptors do not appear to mediate the disruptive effects of mitragynine on learned behavior. Mitragynine had lesser antinociceptive effects than morphine, and these did not appear to be mediated by opioid receptors. The pharmacology of mitragynine includes a substantial non-opioid mechanism.

Characteristics of deaths associated with kratom use

BACKGROUND

Kratom (Mitragyna speciosa Korth) use has increased in Western countries, with a rising number of associated deaths. There is growing debate about the involvement of kratom in these events.

AIMS

This study details the characteristics of such fatalities and provides a 'state-of-the-art' review.

METHODS

UK cases were identified from mortality registers by searching with the terms 'kratom', 'mitragynine', etc. Databases and online media were searched using these terms and 'death', 'fatal*', 'overdose', 'poisoning', etc. to identify additional cases; details were obtained from relevant officials. Case characteristics were extracted into an Excel spreadsheet, and analysed employing descriptive statistics and thematic analysis.

RESULTS

Typical case characteristics (n = 156): male (80%), mean age 32.3 years, White (100%), drug abuse history (95%); reasons for use included self-medication, recreation, relaxation, bodybuilding, and avoiding positive drug tests. Mitragynine alone was identified/implicated in 23% of cases. Poly substance use was common (87%), typically controlled/recreational drugs, therapeutic drugs, and alcohol. Death cause(s) included toxic effects of kratom ± other substances; underlying health issues.

CONCLUSIONS

These findings add substantially to the knowledge base on kratom-associated deaths; these need systematic, accurate recording. Kratom's safety profile remains only partially understood; toxic and fatal levels require quantification.

The Trouble With Kratom: Analytical and Interpretative Issues Involving Mitragynine

Mitragynine is the primary active alkaloid in the leaves of the tropical tree Mitragyna speciosa, and goes by the popular names “Kratom”, biak-biak and maeng da. Mitragynine is increasingly seen in forensic toxicology casework including driving under the influence of drugs and medicolegal death investigation cases. The toxicity of mitragynine continues to be debated in the scientific community as advocates highlight its long history of use in Southeast Asia and testimonials to its benefits by present-day users, while opponents point to an increasing number of adverse events tied to mitragynine use in Western societies. Quantitative reports of mitragynine in biological specimens from forensic investigations in the literature are sparse and may be influenced by poor analyte stability and inadequate resolution of mitragynine from its diastereomers, which could lead to falsely elevated concentrations and subsequently render those reported concentrations inappropriate for comparison to a reference range. Over the course of 27 months, 1,001 blood specimens submitted to our laboratory tested positive for mitragynine using a sensitive and specific quantitative LC-MS/MS method; concentrations ranged from 5.6–29,000 ng/mL, with mean and median concentrations of 410 ± 1,124 and 130 ng/mL, respectively. Mitragynine presents an analytical challenge that requires a method that appropriately separates and identifies mitragynine itself from its isomers and other related natural products. We describe a validated analytical method and present a short series of case reports that provide examples of apparent adverse events, and the associated range of mitragynine concentrations. This type of analytical specificity is required to appropriately interpret mitragynine concentrations detected in biological specimens from forensic casework and assess its potential toxicity.

The unsuspected threat of three opioid-like substitutes

The opioid epidemic has left its toll on the United States with millions suffering from an opioid use disorder and tens of thousands dying from overdoses each year. With intentions to combat the crisis, health providers have been prescribing less opioids, which resulted in an unintentional increase in the abuse of other opioid-like substances. Three emerging drugs of abuse have been noted in the literature as having increased abuse potential in light of recent trends. Kratom, an herbal supplement, gabapentin, a prescription nerve pain and anticonvulsant medication, and loperamide, an over-the-counter antidiarrheal medication. These have all displayed opioid-like properties at high doses and used to alleviate opioid withdrawal. Healthcare clinicians and patients might not be aware of the potential risks involved with misusing or abusing these opioid substitutes. This article discusses the increased usage of kratom, gabapentin, and loperamide, the abuse potential, adverse effects and withdrawal symptoms of each drug, and nursing implications that impact inpatient safety and management.

7-Hydroxymitragynine Is an Active Metabolite of Mitragynine and a Key Mediator of Its Analgesic Effects

Mitragyna speciosa, more commonly known as kratom, is a plant native to Southeast Asia, the leaves of which have been used traditionally as a stimulant, analgesic, and treatment for opioid addiction. Recently, growing use of the plant in the United States and concerns that kratom represents an uncontrolled drug with potential abuse liability, have highlighted the need for more careful study of its pharmacological activity. The major active alkaloid found in kratom, mitragynine, has been reported to have opioid agonist and analgesic activity in vitro and in animal models, consistent with the purported effects of kratom leaf in humans. However, preliminary research has provided some evidence that mitragynine and related compounds may act as atypical opioid agonists, inducing therapeutic effects such as analgesia, while limiting the negative side effects typical of classical opioids. Here we report evidence that an active metabolite plays an important role in mediating the analgesic effects of mitragynine. We find that mitragynine is converted in vitro in both mouse and human liver preparations to the much more potent mu-opioid receptor agonist 7-hydroxymitragynine and that this conversion is mediated by cytochrome P450 3A isoforms. Further, we show that 7-hydroxymitragynine is formed from mitragynine in mice and that brain concentrations of this metabolite are sufficient to explain most or all of the opioid-receptor-mediated analgesic activity of mitragynine. At the same time, mitragynine is found in the brains of mice at very high concentrations relative to its opioid receptor binding affinity, suggesting that it does not directly activate opioid receptors. The results presented here provide a metabolism-dependent mechanism for the analgesic effects of mitragynine and clarify the importance of route of administration for determining the activity of this compound. Further, they raise important questions about the interpretation of existing data on mitragynine and highlight critical areas for further research in animals and humans.

The Use of Benzodiazepines among Kratom (Mitragyna Speciosa Korth.) Users

The leaves from Mitragyna speciosa (Korth.) trees, also known as kratom, are traditionally used in Southeast Asia as a mild psychotropic agent. We investigated the demographic characteristics of persons who used both kratom cocktail and benzodiazepines (BZO) in a sample drawn from a rural area in Penang, Malaysia, and the reasons for BZO use. Seventy-seven participants who currently use a kratom cocktail along with BZO were recruited through snowball sampling for this cross-sectional study. The participants were male, and the majority were Malays (99%, n = 76/77), single (57%, n = 44/77) and employed (91%, n = 70/77). BZO was used with kratom cocktail 1) to increase euphoria; 2) to reduce dependence on methamphetamine; 3) to promote sleep; 4) to ease methamphetamine-associated psychological symptoms and 5) to decrease the craving for kratom. There were no significant differences in the intake of kratom use (p = .751), BZO use duration (p = .259), frequency (p = .188) and quantity (p = .888) of BZO use in the last 7 days, and quantity of BZO use in the last 30 days (p = .337) between kratom users and kratom poly-drug users. An awareness of the health consequences of the co-use of kratom with BZO is needed to prevent untoward health incidents.

Kratom and General Anesthesia: A Case Report and Review of the Literature

Kratom is a botanical substance derived from the Mitragyna speciosa plant, which grows naturally in Southeast Asia. Its active compounds include alkaloids with psychoactive and opioid properties. Low doses act as a stimulant, while higher doses cause analgesia and euphoria. As a drug of abuse, there are reports of seizure, acute psychosis, and death. Both the US Food and Drug Administration and the Drug Enforcement Agency warn against the use of kratom. Here is the first reported case of an anesthetic in a patient using kratom for chronic pain.

Kratom policy: The challenge of balancing therapeutic potential with public safety

Kratom (Mitragyna speciosa) is a tree-like plant indigenous to Southeast Asia. Its leaves, and the teas brewed from them have long been used by people in that region to stave off fatigue and to manage pain and opioid withdrawal. Evidence suggests kratom is being increasingly used by people in the United States and Europe for the self-management of opioid withdrawal and treatment of pain. Recent studies have confirmed that kratom and its chemical constituents have potentially useful pharmacological actions. However, there have also been increasing numbers of reports of adverse effects resulting from use of kratom products. In August 2016, the US Drug Enforcement Administration announced plans to classify kratom and its mitragynine constituents as Schedule I Controlled Substances, a move that triggered a massive response from pro-kratom advocates. The debate regarding the risks, and benefits and safety of kratom continues to intensify. Kratom proponents tout kratom as a safer and less addictive alternative to opioids for the management of pain and opioid addiction. The anti-kratom faction argues that kratom, itself, is a dangerous and addictive drug that ought to be banned. Given the widespread use of kratom and the extensive media attention it is receiving, it is important for physicians, scientists and policy makers to be knowledgeable about the subject. The purpose of this commentary is to update readers about recent developments and controversies in this rapidly evolving area. All of the authors are engaged in various aspects of kratom research and it is our intention to provide a fair and balanced overview that can form the basis for informed decisions on kratom policy. Our conclusions from these analyses are: (a) User reports and results of preclinical studies in animals strongly suggest that kratom and its main constituent alkaloid, mitragynine may have useful activity in alleviating pain and managing symptoms of opioid withdrawal, even though well-controlled clinical trials have yet to be done. (b) Even though kratom lacks many of the toxicities of classic opioids, there are legitimate concerns about the safety and lack of quality control of purported "kratom" products that are being sold in the US. (c) The issues regarding the safety and efficacy of kratom and its mitragynine constituent can only be resolved by additional research. Classification of the Mitragyna alkaloids as Schedule I controlled substances would substantially impede this important research on kratom.

Non-Prescribed Buprenorphine Use Mediates the Relationship between Heroin Use and Kratom Use among a Sample of Polysubstance Users

In Asia, Mitragyna speciosa (e.g., "kratom") has been used to mitigate alcohol and drug dependence. Some preliminary findings suggest kratom's potential use as an informal harm-reduction method in the United States, such as an opioid substitute or as a means of lessening opioid withdrawal symptoms. To determine correlates of past-year kratom use among a sample of polysubstance users enrolled in residential recovery programs in Kentucky, an anonymous survey was completed by clients in April 2017. Logistic regression was used to identify significant associations with past-year kratom use. Of the final sample (N = 478), 10.4% reported past-year kratom use. Past-year heroin use, but not past-year prescription opioid (e.g., oxycodone, hydrocodone) use, was significantly associated with kratom use, such that individuals who reported past-year heroin use were 2.5 times more likely to also report past-year kratom use. Non-prescribed buprenorphine (i.e., Suboxone) use partially mediated the relationship between past-year heroin and kratom use by explaining 36% of the association between the two drugs. Though amphetamines were highly preferred, past-year use was negatively correlated with past-year kratom use. Rates of past-year kratom use were lower than rates of alcohol and illicit drug use. Kratom was not preferred over heroin or prescription opioids.

Mitragyna speciosa: Clinical, Toxicological Aspects and Analysis in Biological and Non-Biological Samples

The abuse of psychotropic substances is a well-known phenomenon, and many of them are usually associated with ancestral traditions and home remedies. This is the case of Mitragyna speciosa (kratom), a tropical tree used to improve work performance and to withstand great heat. According to several published studies, the main reasons for kratom consumption involve improving sexual performance and endurance, but also social and recreational uses for the feeling of happiness and euphoria; it is also used for medical purposes as a pain reliever, and in the treatment of diarrhea, fever, diabetes, and hypertension. However, this plant has gained more popularity amongst young people over the last years. Since it is available on the internet for purchase, its use is now widely as a drug of abuse, namely as a new psychoactive substance, being a cheaper alternative to opioids that does not require medical prescription in most countries. According to internet surveys by the European Monitoring Centre for Drugs and Drug Addiction in 2008 and 2011, kratom was one of the most widely supplied new psychoactive substances. The composition of kratom is complex; in fact, more than 40 different alkaloids have been identified in Mitragyna speciosa so far, the major constituent being mitragynine, which is exclusive to this plant. Besides mitragynine, alkaloids such as corynantheidine and 7-hydroxamitragynine also present pharmacological effects, a feature that may be attributed to the remaining constituents as well. The main goal of this review is not only to understand the origin, chemistry, consumption, and analytical methodologies for analysis and mechanism of action, but also the use of secondary metabolites of kratom as therapeutic drugs and the assessment of potential risks associated with its consumption, in order to aid health professionals, toxicologists, and police authorities in cases where this plant is present.

Non-Medical Use of Novel Synthetic Opioids: A New Challenge to Public Health

Background: In the last decade there has been a progressive increase in the use of new psychoactive substances (NPSs) that are not yet under international control. In particular, novel synthetic opioids (NSOs) have reappeared on the recreational drug market in the last few years. As a result, the use of NSOs has increased rapidly. This poses an emerging and demanding challenge to public health. Aim: To raise awareness among clinicians and other professionals about NPSs, especially NSOs, to summarize current knowledge about pharmacological properties, forms of NSO on the market, pattern of use, effects and consequences of use. Methods: An electronic search was carried out on the Medline/PubMed and Google Scholar databases to find selected search terms. Results: Some NPSs are already controlled, while others can be legally sold directly on the drug market (mainly via internet, less so by drug dealers) or be used as precursors for the synthesis of other designer drugs that mimic the psychoactive effects of controlled substances. Potential side-effects of NSOs include miosis, sedation, respiratory depression, hypothermia, inhibition of gastrointestinal propulsion, death (from opioid overdose). Conclusions: The severity of the opioid crisis has intensified with the introduction of highly potent NSOs on the drug market. As long as addicts are dying from overdose or similar causes, there is something more constructive to do than waiting for addicts to overdose on heroin at a place located near a remedy, as if to say, within reach of naloxone.

Metabolite profiling and identification of enzymes responsible for the metabolism of mitragynine, the major alkaloid of Mitragyna speciosa (kratom)

1. Mitragynine is the major indole-based alkaloid of Mitragyna speciosa (kratom). Decoctions (teas) of the plant leaves have been used traditionally for cough, diarrhoea, pain, hypertension and for the treatment of opioid addiction. In the West, kratom has become increasingly utilized for mood elevation, pain treatment and as a means of self-treating opioid addiction. 2. Metabolic pathways of mitragynine were identified in human liver microsomes (HLM) and S9 fractions. A total of thirteen metabolites were identified, four oxidative metabolites and a metabolite formed by demethylation at the 9-methoxy group were the major metabolites of mitragynine. 3. The cytochrome P450 enzymes involved in the metabolism of mitragynine were identified using selective chemical inhibitors of HLM and recombinant cytochrome P450. The metabolism of mitragynine was predominantly carried out through the CYP3A4 with minor contributions by CYP2D6 and CYP2C9. The formation of five oxidative metabolites (Met2, Met4, Met6, Met8 and Met11) was catalyzed by the CYP3A4. 4. In summary, mitragynine was extensively metabolized in HLM primarily to O-demethylated and mono-oxidative metabolites. The CYP3A4 enzyme plays a predominant role in the metabolic clearance of mitragynine and also in the formation of 7-hydroxymitragynine (Met2), a known active minor alkaloid identified in the leaf material.

Severity of Kratom (Mitragyna speciosa Korth.) Psychological Withdrawal Symptoms

Kratom leaves (Mitragyna speciosa Korth.) are traditionally used in Southeast Asia for their medicinal value. Self-report studies suggest that cessation from chronic kratom tea consumption (freshly brewed kratom tea) was associated with unpleasant psychological symptoms. This study sought to assess the severity of anxiety and depression during kratom cessation. Regular kratom users (N = 150) were recruited from the northern state of Penang (Malaysia) for this retrospective study. The Beck Depression Inventory (BDI) and Beck Anxiety Inventory (BAI) scales were used to assess the severity of the symptoms of anxiety and depression. Most respondents (70%) experienced symptoms of mild anxiety, while 81% experienced symptoms of mild depression during kratom cessation. Those who consumed higher quantities of kratom tea daily (≥4 glasses) had higher odds of reporting longer duration of kratom use history (OR = 4.8, 95% CI 2.3 -10.1, p < 0.001), higher frequency of daily kratom use (≥4 times) (OR = 72, CI 9.5- 543.1, p < 0.001), and were more likely to experience moderate symptoms of depression (OR = 2.9, CI 1.1-7.3, p = 0.020) during kratom cessation than those who consumed between one and three glasses of kratom tea per day. Cessation from regular and long-term kratom tea consumption was not associated with symptoms of high anxiety or depression.

Fatal Mitragynine-Associated Toxicity in Canada: A Case Report and Review of the Literature

Mitragynine is amongst the more than 40 natural indole alkaloids derived from the Mitragyna speciosa, or kratom tree, also referred to as ketum. The compound is unique in that it exhibits dose-dependent clinical outcomes with stimulant effects at lower doses but sedative effects at higher concentrations. It is indigenous to Southeast Asia, where the local population has had extensive experiences utilizing the substance for its medicinal as well as recreational effects. Mitragynine is advertised as an herbal remedy and is readily accessible via the Internet, resulting in its expansive distribution throughout the world. The addictive potential of this substance is quickly becoming recognized and mitragynine has been implicated in multidrug toxicity deaths. We present a case of the first reported mitragynine-associated fatality in Canada where an independently fatal mitragynine concentration was detected in the postmortem femoral venous blood and the source drug was likely obtained as a powder from Indonesia. Acad Forensic Pathol. 2018 8(2): 340-346.

Evaluating the hematological and clinical-chemistry parameters of kratom (Mitragyna speciosa) users in Malaysia

ETHNOPHARMACOLOGICAL RELEVANCE

Kratom (Mitragyna speciosa Korth.) from the Rubiaceae family is an indigenous tropical medicinal tree of Southeast Asia. Kratom leaves have been used for decades in Malaysia and Thailand in traditional context for its perceived vast medicinal value, and as a mild stimulant among manual labourers. Kratom consumption has been reported to cause side-effects in kratom users.

AIM OF THE STUDY

To evaluate kratom's effects towards hematological and clinical-chemistry parameters among regular kratom users in Malaysia.

METHODS

A total of 77 subjects (n=58 regular kratom users, and n=19 healthy controls) participated in this cross-sectional study. All the surveys were conducted through face-to-face interview to elicit subject's socio-demographic characteristics and kratom use history. A full-blood test was also administered. Laboratory analysis was conducted using GC-MS to determine mitragynine content in the acquired kratom samples in order to relate mitragynine consumption with possible alterations in the blood parameters of kratom users.

RESULTS

Findings showed that there were no significant differences in the hematological and clinical-chemistry parameters of traditional kratom users and healthy controls, except for HDL and LDL cholesterol values; these were found to be above the normal reference range for the former. Similarly, long-term kratom consumption (>5 years), and quantity of daily kratom use (≥3 ½ glasses; mitragynine content 76.3-114.8mg) did not appear to alter the hematological and biochemical parameters of kratom users.

CONCLUSION

These data suggest that even long-term and heavy kratom consumption did not significantly alter the hematological and clinical-chemistry parameters of kratom users in a traditional setting.

Severity of Pain and Sleep Problems during Kratom (Mitragyna speciosa Korth.) Cessation among Regular Kratom Users

Kratom (Mitragyna speciosa Korth.) is traditionally used in Southeast Asia for its medicinal value and psychoactive properties. Nonetheless, cessation from regular kratom use is reported to cause unpleasant dose-dependent withdrawal symptoms. This study aims to evaluate the severity of pain and sleep problems following the cessation of kratom tea/juice consumption among regular kratom users. A total of 170 regular users were recruited through snowball sampling for this cross-sectional study. The Brief Pain Inventory (BPI) and Pittsburgh Sleep Quality Index (PSQI) scales were administered to assess the severity of pain and sleep problems. Most participants experienced moderate pain intensity (84%) and moderate pain interference (70%) during kratom cessation; 46% experienced more sleep problems during kratom cessation. Individuals who consumed ≥4 glasses of kratom tea/juice (about 76-115 mg of mitragynine) daily had higher odds of reporting some pain interference (OR: 2.0; CI: 1.04-3.93: p < .028), and sleep problems during kratom cessation (OR: 2.0; CI: 1.08-3.68: p < .020), as compared to those who consumed 1-3 glasses of kratom tea/juice daily. However, the effects were still relatively mild. Cessation from regular kratom tea/juice consumption is not associated with prolonged pain and sleep problems, as compared to those reported for opioid analgesics.

Kratom use and mental health: A systematic review

BACKGROUND

Kratom (Mitragyna speciosa) is a psychoactive plant native to Southeastern Asia that is receiving increased international attention as a potential therapeutic agent. While much of the limited scientific research on kratom is focused on its analgesic potential, kratom use also has important risks and benefits in the domain of mental health.

METHODS

We conducted a comprehensive systematic review of all studies on kratom use and mental health published between January 1960 and July 2017.

RESULTS

Findings indicate kratom's potential as a harm reduction tool, most notably as a substitute for opioids among people who are addicted. Kratom also enhances mood and relieves anxiety among many users. For many, kratom's negative mental health effects - primarily withdrawal symptoms - appear to be mild relative to those of opioids. For some users, however, withdrawal is highly uncomfortable and maintaining abstinence becomes difficult.

CONCLUSION

Results inform clinicians working in the mental health and substance use fields, policy-makers, and researchers about the mental health effects of this plant.

The abuse potential of kratom according the 8 factors of the controlled substances act: implications for regulation and research

RATIONALE

Consideration by the US Drug Enforcement Administration and Food and Drug Administration of placing kratom into Schedule I of the Controlled Substances Act (CSA) requires its evaluation of abuse potential in the context of public health.

OBJECTIVE

The objective of the study is to provide a review of kratom abuse potential and its evaluation according to the 8 factors of the CSA.

RESULTS

Kratom leaves and extracts have been used for centuries in Southeast Asia and elsewhere to manage pain and other disorders and, by mid-twentieth century, to manage opioid withdrawal. Kratom has some opioid effects but low respiratory depression and abuse potential compared to opioids of abuse. This appears due to its non-opioid-derived and resembling molecular structure recently referred to as biased agonists. By the early 2000s, kratom was increasingly used in the US as a natural remedy to improve mood and quality of life and as substitutes for prescription and illicit opioids for managing pain and opioid withdrawal by people seeking abstinence from opioids. There has been no documented threat to public health that would appear to warrant emergency scheduling of the products and placement in Schedule I of the CSA carries risks of creating serious public health problems.

CONCLUSIONS

Although kratom appears to have pharmacological properties that support some level of scheduling, if it was an approved drug, placing it into Schedule I, thus banning it, risks creating public health problems that do not presently exist. Furthermore, appropriate regulation by FDA is vital to ensure appropriate and safe use.

Self-Experiments with Psychoactive Substances: A Historical Perspective

The purpose of this chapter is to highlight the rich tradition of self-experiments (SEs) with psychoactive substances carried out by scientists and therapists for more than a century. Scientifically inspired controlled SEs dominated until the end of the twentieth century, when ethical requirements minimized controlled SEs and "wild" SEs expanded particularly with the emergence of new psychoactive substances. The review focuses on laughing gas (nitrous oxide), cannabis, cocaine, hallucinogens, entactogens, and dissociative hallucinogens. This is due to the fact that substances that induce "complex" effects such as alteration of space/time experience, ego dissolution, and increased feelings and insights (e.g., hallucinogens, entactogens) represent by far the majority of SEs, whereas SEs with substances inducing "simple" effects such as euphoria, anxiolysis, dissociation, or emotional blunting (e.g., cocaine, opioids) are much rarer or even absent (e.g., benzodiazepines). Complex drug effects are much harder to describe, thus allowing SEs to fulfill a more important function.SEs with psychoactive drugs appeared to emerge in the mid-eighteenth century, which triggered a long-standing tradition throughout the nineteenth and early twentieth century. SEs have been de facto performed for a variety of reasons, ranging from establishing scientific knowledge and gaining philosophical insights to compensating for personal deficits. Self-experimenters can be divided into two general types. Besides their scientific intentions, "exploratory" self-experimenters intend to expand awareness and insight, whereas "compensatory" self-experimenters might aim for coping with psychiatric symptoms or personality deficits. Scientific limitations of SEs are obvious when compared to double-blind, randomized, placebo-controlled trials. Whereas the former might lead to more "realistic" detailed description of subjective effects, the latter lead to more solid results in respect to objectively measurable "average" effects. Possible adverse effects of SEs were identified that resulted in loss of scientific objectivity and decreased control over substance use and addiction, development of isolation, problematic group dynamics, and "social autism."

Pharmacologic and clinical assessment of kratom

PURPOSE

This article reviews the pharmacology, clinical utility, adverse effects, and abuse potential of kratom.

SUMMARY

The leaves of Mitragyna speciosa contain the biologically active alkaloids of kratom. Kratom exerts opioid and α-2 receptor agonistic effects as well as antiinflammatory and parasympathetic-impeding effects. There are no published human pharmacologic, pharmacokinetic, or drug interaction studies on kratom or mitragynine, making it virtually impossible to fully understand kratom's therapeutic potential and risks and the populations most likely to benefit or experience harm from its use. Kratom has been used to ameliorate opioid withdrawal symptoms but also induces withdrawal. Human pharmacologic, pharmacokinetic, and clinical data are of low quality, precluding any firm conclusions regarding safety and efficacy. Respiratory depression has not been commonly reported, but kratom does cause a host of adverse effects without clear guidance for how they should be treated. There are numerous assessments where people have been unable to stop using kratom therapy, and withdrawal signs and symptoms are problematic. Kratom does not appear in normal drug screens and, when taken with other substances of abuse, may not be recognized. Thirty-six deaths have been attributed to kratom, and the Food and Drug Administration issued a public health warning about the substance in November 2017.

CONCLUSION

Kratom exerts opioid and α-2 receptor agonistic effects as well as antiinflammatory and parasympathetic-impeding effects. Human pharmacologic, pharmacokinetic, and clinical data are of low quality, precluding any firm conclusions regarding safety and efficacy.

Prevalence and motivations for kratom use in a sample of substance users enrolled in a residential treatment program

BACKGROUND

Kratom use in the West has increased recently, yet the prevalence and motives for use among individuals with a history of substance use disorder (SUD) have not been fully examined. Kratom has been documented as a means of treating chronic pain, mitigating drug dependence, and easing withdrawal symptoms, yet it is unclear if substance users are utilizing kratom as a self-medication. Abuse liability, side effects, and overall appeal of kratom remain uncertain.

METHODS

In April 2017, an anonymous survey regarding kratom use and motivations was completed by clients enrolled in a 12-Step-oriented residential program. 500 respondents with a self-reported history of SUD completed the survey.

RESULTS

20.8% of respondents endorsed lifetime kratom use and 10.2% reported past-12-month use. Kratom-users were younger (=32.1 vs. 35.9, p<0.001) and were more versatile substance users. A majority (68.9%) of kratom-users reported having used the drug as a means of reducing or abstaining from non-prescription opioids (NPO) and/or heroin, and 64.1% reported using kratom as a substitute for NPO/heroin. 18.4% of kratom-users reported using the drug due to a disability or chronic pain. One-third of kratom-users stated that kratom was a helpful substance and that they would try it again. However, kratom was not preferred and was indicated as having less appeal than NPO, heroin, amphetamines, and Suboxone.

CONCLUSIONS

Among substance users, kratom use may be initiated for a variety of reasons, including as a novel form of harm-reduction or drug substitution, particularly in the context of dependence and withdrawal from other substances.

Update on the Pharmacology and Legal Status of Kratom

Kratom (Mitragyna speciosa) is a plant indigenous to Southeast Asia. Its leaves and the teas brewed from them have long been used by people in that region to stave off fatigue and to manage pain and opioid withdrawal. In a comprehensive review published in 2012, Prozialeck et al presented evidence that kratom had been increasingly used for the self-management of opioid withdrawal and pain in the United States. At the time, kratom was classified as a legal herbal product by the US Drug Enforcement Administration. Recent studies have confirmed that kratom and its chemical constituents do have useful pharmacologic actions. However, there have also been increasing numbers of reports of adverse effects resulting from use of kratom products. In August 2016, the US Drug Enforcement Administration announced plans to classify kratom and its mitragynine constituents as Schedule 1 controlled substances, a move that triggered a massive response from kratom advocates. The purpose of this report is to highlight the current scientific and legal controversies regarding kratom.

The medicinal chemistry and neuropharmacology of kratom: A preliminary discussion of a promising medicinal plant and analysis of its potential for abuse

The leaves of Mitragyna speciosa (commonly known as kratom), a tree endogenous to parts of Southeast Asia, have been used traditionally for their stimulant, mood-elevating, and analgesic effects and have recently attracted significant attention due to increased use in Western cultures as an alternative medicine. The plant's active alkaloid constituents, mitragynine and 7-hydroxymitragynine, have been shown to modulate opioid receptors, acting as partial agonists at mu-opioid receptors and competitive antagonists at kappa- and delta-opioid receptors. Furthermore, both alkaloids are G protein-biased agonists of the mu-opioid receptor and therefore, may induce less respiratory depression than classical opioid agonists. The Mitragyna alkaloids also appear to exert diverse activities at other brain receptors (including adrenergic, serotonergic, and dopaminergic receptors), which may explain the complex pharmacological profile of raw kratom extracts, although characterization of effects at these other targets remains extremely limited. Through allometric scaling, doses of pure mitragynine and 7-hydroxymitragynine used in animal studies can be related to single doses of raw kratom plant commonly consumed by humans, permitting preliminary interpretation of expected behavioral and physiological effects in man based on this preclinical data and comparison to both anecdotal human experience and multiple epidemiological surveys. Kratom exposure alone has not been causally associated with human fatalities to date. However, further research is needed to clarify the complex mechanism of action of the Mitragyna alkaloids and unlock their full therapeutic potential. This article is part of the Special Issue entitled 'Designer Drugs and Legal Highs.'

The effects of kratom on restraint-stress-induced analgesia and its mechanisms of action

ETHNOPHARMACOLOGICAL RELEVANCE

Mitragyna speciosa and its extracts are called kratom (dried leaves, extract). They contain several alkaloids with an affinity for different opioid receptors. They are used in traditional medicine for the treatment of different diseases, as a substitute by opiate addicts, and to mitigate opioid withdrawal symptoms. Apart from their medical properties, they are used to enhance physical endurance and as a means of overcoming stress.

PURPOSE

The aim of this study was to determine the mechanisms underlying the effects of kratom on restraint-stress-induced analgesia which occurs during or following exposure to a stressful or fearful stimulus.

METHODS

To gain further insights into the action of kratom on stress, we conducted experiments using restraint stress as a test system and stress-induced analgesia as a test parameter. Using transgenic mu opioid-receptor (MOR) deficient mice, we studied the involvement of this receptor type. We used nor-binaltorphimine (BNT), an antagonist at kappa opioid receptors (KOR), to study functions of this type of receptor. Membrane potential assay was also employed to measure the intrinsic activity of kratom in comparison to U50,488, a highly selective kappa agonist.

RESULTS

Treatment with kratom diminished stress-induced analgesia in wildtype and MOR knockout animals. Pretreatment of MOR deficient mice with BNT resulted in similar effects. In comparison to U50,488, kratom exhibited negligible intrinsic activity at KOR alone.

CONCLUSIONS

The results suggest that the use of kratom as a pharmacological tool to mitigate withdrawal symptoms is related to its action on KOR.

Herbal Highs: Review on Psychoactive Effects and Neuropharmacology

BACKGROUND

A new trend among users of new psychoactive substances' the consumption of "herbal highs": plant parts containing psychoactive substances. Most of the substances extracted from herbs, in old centuries were at the centre of religious ceremonies of ancient civilizations. Currently, these herbal products are mainly sold by internet web sites and easily obtained since some of them have no legal restriction.

OBJECTIVE

We reviewed psychoactive effects and neuropharmacology of the most used "herbal highs" with characterized active principles, with studies reporting mechanisms of action, pharmacological and subjective effects, eventual secondary effects including intoxications and/or fatalities Method: The PubMed database was searched using the following key.words: herbal highs, Argyreia nervosa, Ipomoea violacea and Rivea corymbosa; Catha edulis; Datura stramonium; Piper methysticum; Mitragyna speciosa.

RESULTS

Psychoactive plants here reviewed have been known and used from ancient times, even if for some of them limited information still exist regarding subjective and neuropharmacological effects and consequent eventual toxicity when plants are used alone or in combination with "classical" drugs of abuse.

CONCLUSION

Some "herbal highs" should be classified as harmful drugs since chronic administration has been linked with addiction and cognitive impairment; for some others taking into consideration only the recent trends of abuse, studies investigating these aspects are lacking.

Novel Psychoactive Substances-Recent Progress on Neuropharmacological Mechanisms of Action for Selected Drugs

A feature of human culture is that we can learn to consume chemical compounds, derived from natural plants or synthetic fabrication, for their psychoactive effects. These drugs change the mental state and/or the behavioral performance of an individual and can be instrumentalized for various purposes. After the emergence of a novel psychoactive substance (NPS) and a period of experimental consumption, personal and medical benefits and harm potential of the NPS can be estimated on evidence base. This may lead to a legal classification of the NPS, which may range from limited medical use, controlled availability up to a complete ban of the drug form publically accepted use. With these measures, however, a drug does not disappear, but frequently continues to be used, which eventually allows an even better estimate of the drug's properties. Thus, only in rare cases, there is a final verdict that is no more questioned. Instead, the view on a drug can change from tolerable to harmful but may also involve the new establishment of a desired medical application to a previously harmful drug. Here, we provide a summary review on a number of NPS for which the neuropharmacological evaluation has made important progress in recent years. They include mitragynine ("Kratom"), synthetic cannabinoids (e.g., "Spice"), dimethyltryptamine and novel serotonergic hallucinogens, the cathinones mephedrone and methylone, ketamine and novel dissociative drugs, γ-hydroxybutyrate, γ-butyrolactone, and 1,4-butanediol. This review shows not only emerging harm potentials but also some potential medical applications.

Biochemical Benefits, Diagnosis, and Clinical Risks Evaluation of Kratom

BACKGROUND

Kratom (Mitragyna speciosa) is a tropical tree with a long history of traditional use in parts of Africa and Southeast Asia. Kratom is also known as Thom, Thang, and Biak. Its leaves and the teas brewed from them have long been used by people in that region to manage pain and opioid withdrawal and to stave off fatigue. Kratom is actually consumed throughout the world for its stimulant effects and as an opioid substitute (in form of tea, chewed, smoked, or ingested in capsules). Some case reports have associated kratom exposure with psychosis, seizures, intrahepatic cholestasis, other medical conditions, and deaths. The clinical manifestations of kratom effects are not well defined and the clinical studies are limited. Data research suggest that both stimulant and sedative dose-dependent effects do exist, in addition to antinociceptive, antidepressant activity, anxiolytic-like effects, and anorectic effects, but a growing concern for the drug's effects and safety of use has resulted in national and international attention primarily due to an increase in hospital visits and deaths in several countries that are believed to have been caused by extracts of the plant. There is a dearth of double blind controlled studies. In this study, we aim to use existing literature to clarify both benefits and risks of kratom as well as its diagnosis evaluation as kratom misuse is an emerging trend in the Western world.

METHODS

Literature review using databases such as Embase, Medline, PubMed, Cochrane Library, and Mendeley from 2007 to 2017 were evaluated by all authors to analyze current state on benefits, risks, and diagnosis evaluation of kratom (M. speciosa).

RESULTS

Data analysis suggested that kratom possesses some benefits such as stimulant and sedative effects as wells as antinociceptive effects. It seems to inhibit pro-inflammatory mediator release and vascular permeability and can enhance immunity. In addition, it may be an antidepressant and anorectic. However, kratom can cause intrahepatic cholestasis, seizure, arrhythmia, impair memory function, coma, and death. Psychological manifestations described are euphoria and feeling relaxed to severe symptoms such as aggression, hostility, and psychosis. Medical manifestations described are polyuria, dry mouth, vomiting, and jerky movements. Currently, liquid chromatography/mass spectrometry and ion mobility spectrometry (IMS) are suggested as the most promising to rapidly screen kratom products providing a positive success rate.

CONCLUSION

Our data analysis has not determined if biochemical benefits of kratom may prove to outweigh its toxicity and risks. On the contrary, it seems that its potential side effects outweigh the benefits, and severe and real health hazards can, insidiously, lead to death. Kratom clinical, psychological, and medical manifestations can be disturbing. Kratom (M. speciosa) use, among multiple compounds of the leaf, appear to be increasing in the Western world. Promising methods to accurately identify kratom compounds are still ongoing.

Traditional and non-traditional uses of Mitragynine (Kratom): A survey of the literature

INTRODUCTION

The objective of the paper was to highlight the differences in the traditional and non-traditional users of kratom in the South East Asian and Western contexts.

METHOD

A literature survey of published kratom studies among humans was conducted. Forty published studies relevant to the objective were reviewed.

RESULTS

Apart from the differences in the sources of supply, patterns of use and social acceptability of kratom within these two regions, the most interesting finding is its evolution to a recreational drug in both settings and the severity of the adverse effects of kratom use reported in the West. While several cases of toxicity and death have emerged in the West, such reports have been non-existent in South East Asia where kratom has had a longer history of use. We highlight the possible reasons for this as discussed in the literature. More importantly, it should be borne in mind that the individual clinical case-reports emerging from the West that link kratom use to adverse reactions or fatalities frequently pertained to kratom used together with other substances. Therefore, there is a danger of these reports being used to strengthen the case for legal sanction against kratom. This would be unfortunate since the experiences from South East Asia suggest considerable potential for therapeutic use among people who use drugs.

CONCLUSION

Despite its addictive properties, reported side-effects and its tendency to be used a recreational drug, more scientific clinical human studies are necessary to determine its potential therapeutic value.