1
|
Henningfield JE, Grundmann O, Huestis MA, Smith KE. Kratom safety and toxicology in the public health context: research needs to better inform regulation. Front Pharmacol 2024; 15:1403140. [PMID: 38887550 PMCID: PMC11180979 DOI: 10.3389/fphar.2024.1403140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Accepted: 04/30/2024] [Indexed: 06/20/2024] Open
Abstract
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.
Collapse
Affiliation(s)
- Jack E. Henningfield
- Pinney Associates, Inc., Bethesda, MD, United States
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Bethesda, MD, United States
| | - Oliver Grundmann
- College of Pharmacy, Department of Medicinal Chemistry, University of Florida, Gainesville, FL, United States
| | - Marilyn A. Huestis
- Institute of Emerging Health Professions, Thomas Jefferson University, Philadelphia, PA, United States
| | - Kirsten E. Smith
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| |
Collapse
|
2
|
Penzak SR, Durham SH, Phillippe HM, Fox BI. Knowledge of Kratom among Alabama Pharmacists. PHARMACY 2023; 12:6. [PMID: 38251400 PMCID: PMC10801507 DOI: 10.3390/pharmacy12010006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 12/19/2023] [Accepted: 12/28/2023] [Indexed: 01/23/2024] Open
Abstract
Kratom (Mitragyna speciosa) is a botanical substance whose leaves produce stimulant- and opioid-like effects. Kratom use has increased precipitously in the United States (U.S.) over the last decade, yet, in our experience, many pharmacists are unfamiliar with this herb. The purpose of this study was to assess pharmacists' awareness and knowledge of kratom. This cross-sectional study used an online questionnaire to preferentially solicit community pharmacists' knowledge of kratom and collect demographic information. The survey was sent via email to approximately 10,000 pharmacists, targeting those in the state of Alabama, U.S. Data were analyzed using descriptive statistics, and the Chi Square test was used to compare nominal data. A total of 257 participants responded to the survey. Almost 50% of participants had heard of kratom, and 50% had not. Compared to females, males were more likely to have heard of kratom (64% vs. 42%; p = 0.0015), as were pharmacists who worked for an independent pharmacy vs. a chain (61% vs. 41%; p = 0.025). Of the participants who had heard of kratom, only 14% considered themselves knowledgeable or very knowledgeable about the herb, and only 44% knew it was illegal in Alabama. These data indicate a need to further kratom education among community pharmacists in Alabama.
Collapse
Affiliation(s)
- Scott R. Penzak
- Department of Pharmacy Practice, Harrison College of Pharmacy, Auburn University, Auburn, AL 36849-5502, USA; (S.H.D.); (H.M.P.)
| | - Spencer H. Durham
- Department of Pharmacy Practice, Harrison College of Pharmacy, Auburn University, Auburn, AL 36849-5502, USA; (S.H.D.); (H.M.P.)
| | - Haley M. Phillippe
- Department of Pharmacy Practice, Harrison College of Pharmacy, Auburn University, Auburn, AL 36849-5502, USA; (S.H.D.); (H.M.P.)
| | - Brent I. Fox
- Department of Health Outcomes and Research Policy, Harrison College of Pharmacy, Auburn University, Auburn, AL 36849-5502, USA;
| |
Collapse
|
3
|
Prevete E, Kuypers KPC, Theunissen EL, Esposito G, Ramaekers JG, Pasquini M, Corazza O. Clinical Implications of Kratom ( Mitragyna speciosa) Use: a Literature Review. CURRENT ADDICTION REPORTS 2023; 10:317-334. [PMID: 37266188 PMCID: PMC10177737 DOI: 10.1007/s40429-023-00478-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/30/2023] [Indexed: 06/03/2023]
Abstract
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.
Collapse
Affiliation(s)
- Elisabeth Prevete
- Department of Human Neurosciences, Sapienza University of Rome, Viale Dell’Università 30, 00185 Rome, Italy
- Department of Neuropsychology and Psychopharmacology, Faculty of Psychology and Neuroscience, Maastricht University, P.O. Box 616, 6200 MD Maastricht, the Netherlands
| | - Kim Paula Colette Kuypers
- Department of Neuropsychology and Psychopharmacology, Faculty of Psychology and Neuroscience, Maastricht University, P.O. Box 616, 6200 MD Maastricht, the Netherlands
| | - Eef Lien Theunissen
- Department of Neuropsychology and Psychopharmacology, Faculty of Psychology and Neuroscience, Maastricht University, P.O. Box 616, 6200 MD Maastricht, the Netherlands
| | - Gianluca Esposito
- Department of Psychology and Cognitive Science, University of Trento, Corso Bettini, 84, 38068 Rovereto, Italy
| | - Johannes Gerardus Ramaekers
- Department of Neuropsychology and Psychopharmacology, Faculty of Psychology and Neuroscience, Maastricht University, P.O. Box 616, 6200 MD Maastricht, the Netherlands
| | - Massimo Pasquini
- Department of Human Neurosciences, Sapienza University of Rome, Viale Dell’Università 30, 00185 Rome, Italy
| | - Ornella Corazza
- Department of Psychology and Cognitive Science, University of Trento, Corso Bettini, 84, 38068 Rovereto, Italy
- Department of Clinical, Pharmacological and Biological Sciences, University of Hertfordshire, College Lane, Hatfield, AL10 9AB UK
| |
Collapse
|
4
|
Mukhopadhyay S, Gupta S, Wilkerson JL, Sharma A, McMahon LR, McCurdy CR. Receptor Selectivity and Therapeutic Potential of Kratom in Substance Use Disorders. CURRENT ADDICTION REPORTS 2023. [DOI: 10.1007/s40429-023-00472-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
|
5
|
Abstract
Kratom is the common term for Mitragyna speciosa and its products. Its major active compounds are mitragynine and 7-hydroxymitragynine. An estimated 2.1 million US residents used kratom in 2020, as a "legal high" and self-medication for pain, opioid withdrawal, and other conditions. Up to 20% of US kratom users report symptoms consistent with kratom use disorder. Kratom use is associated with medical toxicity and death. Causality is difficult to prove as almost all cases involve other psychoactive substances. Daily, high-dose use may result in kratom use disorder and opioid-like withdrawal on cessation of use. These are best treated with buprenorphine.
Collapse
Affiliation(s)
- David A Gorelick
- Department of Psychiatry, University of Maryland School of Medicine, PO Box 21247, MPRC-Tawes Building, Baltimore, MD 21228, USA.
| |
Collapse
|
6
|
Grundmann O, Hendrickson RG, Greenberg MI. Kratom: History, pharmacology, current user trends, adverse health effects and potential benefits. Dis Mon 2022; 69:101442. [PMID: 35732553 DOI: 10.1016/j.disamonth.2022.101442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Kratom (Mitragyna speciosa Korth.) is a tree native to Southeast Asia with dose-dependent stimulant and opioid-like effects. Dried, powdered leaf material is among the kratom products most commonly consumed in the US and Europe, but other formulations also exist including enriched extracts, resins, tinctures, and edibles. Its prevalence in the US remains debated and the use pattern includes self-treatment of mood disorders, pain, and substance use disorders. Most of the adverse effects of kratom and its alkaloid mitragynine have been reported in the literature as case reports or part of surveys necessitating confirmation by clinical trials. Toxicities associated with kratom consumption have focused on hepatic, cardiac, and CNS effects with the potential to cause fatalities primarily as part of polydrug exposures. Kratom may also present with drug-drug interactions primarily through CYP 3A4 and 2D6 inhibition, although the clinical significance remains unknown to date. The variability in composition of commercially available kratom products complicates generalization of findings and requires further investigation by employing clinical trials. Healthcare professionals should remain cautious in counseling patients on the use of kratom in a therapeutic setting.
Collapse
Affiliation(s)
- Oliver Grundmann
- Department of Medicinal Chemistry, College of Pharmacy, University of Florida, 1345 Center Drive, Room P3-20, Gainesville, FL 32611, United States.
| | | | | |
Collapse
|
7
|
Singh D, Narayanan S, Vicknasingam B, Prozialeck WC, Smith KE, Corazza O, Henningfield JE, Grundmann O. The Use of Kratom (Mitragyna speciosa Korth.) Among People Who Co-use Heroin and Methamphetamine in Malaysia. J Addict Med 2022; 16:223-228. [PMID: 34001777 DOI: 10.1097/adm.0000000000000876] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVES Kratom (Mitragyna speciosa Korth.), an indigenous medicinal plant, has been widely used as a traditional remedy in Southeast Asia. However, its combined consumption with other substances has received scarce attention. This study investigates the use of kratom among adults with a history of using heroin and methamphetamine in Malaysia. METHODS A total of 332 patients who were mandated to undergo drug rehabilitation participated in this cross-sectional study. The study data were collected through face-to-face interviews using a semi-structured questionnaire. RESULTS The majority were males (95%, n = 314/332) and Malays (98%, n = 325/332) with a mean age of 32.3 years (SD = 9.16). Over two thirds of the respondents used kratom to alleviate heroin withdrawal symptoms and to reduce methamphetamine intake; 59% used it as a substitute for heroin and methamphetamine. A similar proportion used kratom to reduce heroin intake (58%), while only 15% used it for its euphoric effects. Multivariate analysis showed that previous attendees of government rehabilitation programs had lower odds of using kratom as a heroin substitute. CONCLUSIONS The potential of kratom to alleviate heroin withdrawal symptoms, and to reduce methamphetamine and heroin intake, among people who co-use heroin and methamphetamine warrants further research.
Collapse
Affiliation(s)
- Darshan Singh
- Centre for Drug Research, Universiti Sains Malaysia, Penang, Malaysia (DS, BV); School of Social Sciences, Universiti Sains Malaysia, Penang, Malaysia (SN); Department of Pharmacology, College of Graduate Studies, Midwestern University, Downers Grove, IL(WCP); National Institute on Drug Abuse Intramural Research Program, Baltimore, MD (KES); Department of Clinical, Pharmaceutical and Biological Sciences, School of Life and Medical Sciences, College Lane, Hatfield, United Kingdom (OC); Pinney Associates, Bethesda, MD and Johns Hopkins University School of Medicine, Baltimore, MD (JEH); Department of Medicinal Chemistry, College of Pharmacy, University of Florida, Gainesville, FL (OG)
| | | | | | | | | | | | | | | |
Collapse
|
8
|
Prevete E, Kuypers KPC, Theunissen EL, Corazza O, Bersani G, Ramaekers JG. A systematic review of (pre)clinical studies on the therapeutic potential and safety profile of kratom in humans. Hum Psychopharmacol 2022; 37:e2805. [PMID: 34309900 PMCID: PMC9285932 DOI: 10.1002/hup.2805] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 07/08/2021] [Indexed: 02/05/2023]
Abstract
INTRODUCTION Kratom (Mitragyna speciosa) is a tropical plant traditionally used as an ethnomedicinal remedy for several conditions in South East Asia. Despite the increased interest in its therapeutical benefits in Western countries, little scientific evidence is available to support such claims, and existing data remain limited to kratom's chronic consumption. OBJECTIVE Our study aims to investigate (pre)clinical evidence on the efficacy of kratom as a therapeutic aid and its safety profile in humans. METHODS A systematic literature search using PubMed and the Medline database was conducted between April and November 2020. RESULTS Both preclinical (N = 57) and clinical (N = 18) studies emerged from our search. Preclinical data indicated a therapeutic value in terms of acute/chronic pain (N = 23), morphine/ethanol withdrawal, and dependence (N = 14), among other medical conditions (N = 26). Clinical data included interventional studies (N = 2) reporting reduced pain sensitivity, and observational studies (N = 9) describing the association between kratom's chronic (daily/frequent) use and safety issues, in terms of health consequences (e.g., learning impairment, high cholesterol level, dependence/withdrawal). CONCLUSIONS Although the initial (pre)clinical evidence on kratom's therapeutic potential and its safety profile in humans is encouraging, further validation in large, controlled clinical trials is required.
Collapse
Affiliation(s)
- Elisabeth Prevete
- Department of Neuropsychology and PsychopharmacologyFaculty of Psychology and NeuroscienceMaastricht UniversityMaastrichtthe Netherlands
| | - Kim Paula Colette Kuypers
- Department of Neuropsychology and PsychopharmacologyFaculty of Psychology and NeuroscienceMaastricht UniversityMaastrichtthe Netherlands
| | - Eef Lien Theunissen
- Department of Neuropsychology and PsychopharmacologyFaculty of Psychology and NeuroscienceMaastricht UniversityMaastrichtthe Netherlands
| | - Ornella Corazza
- Department of Clinical, Pharmacological and Biological SciencesCollege LaneUniversity of HertfordshireHatfieldUnited Kingdom,Department of Medico‐Surgical Sciences and BiotechnologiesFaculty of Pharmacy and MedicineSapienza University of RomeLatinaItaly
| | - Giuseppe Bersani
- Department of Medico‐Surgical Sciences and BiotechnologiesFaculty of Pharmacy and MedicineSapienza University of RomeLatinaItaly
| | - Johannes Gerardus Ramaekers
- Department of Neuropsychology and PsychopharmacologyFaculty of Psychology and NeuroscienceMaastricht UniversityMaastrichtthe Netherlands
| |
Collapse
|
9
|
Hiranita T, Obeng S, Sharma A, Wilkerson JL, McCurdy CR, McMahon LR. In vitro and in vivo pharmacology of kratom. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2021; 93:35-76. [PMID: 35341571 DOI: 10.1016/bs.apha.2021.10.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Kratom products have been historically and anecdotally used in south Asian countries for centuries to manage pain and opioid withdrawal. The use of kratom products has dramatically increased in the United States. More than 45 kratom alkaloids have been isolated, yet the overall pharmacology of the individual alkaloids is still not well characterized. The purpose of this chapter is to summarize in vitro and in vivo opioid activities of the primary kratom alkaloid mitragynine and its more potent metabolite 7-hydroxymitragynine. Following are experimental procedures described to characterize opioid receptor activity; receptor binding and functional assays, antinociceptive assays, operant conditioning assays, and respiratory plethysmography. The capacity of kratom alkaloids to confer tolerance and physical dependence as well as their pharmacokinetic properties are also summarized. The data reviewed here suggest that kratom products and mitragynine possess low efficacy agonist activity at the mu-opioid receptor in vivo. In addition, kratom products and mitragynine have been demonstrated to antagonize the effects of high efficacy mu-opioid agonists. The data further suggest that 7-hydroxymitragynine formed in vivo by metabolism of mitragynine may be minimally involved in the overall behavioral profile of mitragynine and kratom, whereas 7-hydroxymitragynine itself, at sufficiently high doses administered exogenously, shares many of the same abuse- and dependence-related behavioral effects associated with traditional opioid agonists. The apparent low efficacy of kratom products and mitragynine at mu-opioid receptors supports the development of these ligands as effective and potentially safe medications for opioid use disorder.
Collapse
Affiliation(s)
- Takato Hiranita
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, FL, United States
| | - Samuel Obeng
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, FL, United States; Department of Medicinal Chemistry, College of Pharmacy, University of Florida, Gainesville, FL, United States
| | - Abhisheak Sharma
- Department of Pharmaceutics, College of Pharmacy, University of Florida, Gainesville, FL, United States; Translational Drug Development Core, Clinical and Translational Sciences Institute, College of Pharmacy, University of Florida, Gainesville, FL, United States
| | - Jenny L Wilkerson
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, FL, United States
| | - Christopher R McCurdy
- Department of Medicinal Chemistry, College of Pharmacy, University of Florida, Gainesville, FL, United States; Department of Pharmaceutics, College of Pharmacy, University of Florida, Gainesville, FL, United States; Translational Drug Development Core, Clinical and Translational Sciences Institute, College of Pharmacy, University of Florida, Gainesville, FL, United States
| | - Lance R McMahon
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, FL, United States.
| |
Collapse
|
10
|
Hartley C, Bulloch M, Penzak SR. Clinical Pharmacology of the Dietary Supplement, Kratom (Mitragyna speciosa). J Clin Pharmacol 2021; 62:577-593. [PMID: 34775626 DOI: 10.1002/jcph.2001] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 11/05/2021] [Indexed: 11/10/2022]
Abstract
Kratom (Mitragyna speciosa) consists of over 40 alkaloids with two of them, mitragynine (MG) and 7-OH-mitragynine (7-OH-MG) being the main psychoactive compounds. MG and 7-OH-MG each target opioid receptors and have been referred to as atypical opioids. They exert their pharmacologic effects on the μ, δ, and κ opioid receptors. In addition, they affect adrenergic, serotonergic, and dopaminergic pathways. Kratom has been touted as an inexpensive, legal alternative to standard opioid replacement therapy such as methadone and buprenorphine. Other uses for kratom include chronic pain, attaining a "legal high," and numerous CNS disorders including anxiety depression and post-traumatic stress disorder (PTSD). Kratom induces analgesia and mild euphoria with a lower risk of respiratory depression or adverse central nervous system effects compared to traditional opioid medications. Nonetheless, kratom has been associated with both physical and psychological dependence with some individuals experiencing classic opioid withdrawal symptoms upon abrupt cessation. Kratom use has been linked to serious adverse effects including liver toxicity, seizures, and death. These risks are often compounded by poly-substance abuse. Further, kratom may potentiate the toxicity of coadministered medications through modulation of cytochrome P450, P-glycoprotein, and uridine diphosphate glucuronosyltransferase enzymes (UGDT). In 2016 the U.S. Drug Enforcement Administration (DEA) took steps to classify kratom as a federal schedule 1 medication; however, due to public resistance, this plan was set aside. Until studies are conducted that define kratom's role in treating opioid withdrawal and/or other CNS conditions, kratom will likely remain available as a dietary supplement for the foreseeable future. This article is protected by copyright. All rights reserved.
Collapse
Affiliation(s)
- Chad Hartley
- Department of Pharmacy Practice, Harrison School of Pharmacy, Auburn University, Auburn, Alabama, 36849, United States
| | - Marilyn Bulloch
- Department of Pharmacy Practice, Harrison School of Pharmacy, Auburn University, Auburn, Alabama, 36849, United States
| | - Scott R Penzak
- Department of Pharmacy Practice, Harrison School of Pharmacy, Auburn University, Auburn, Alabama, 36849, United States
| |
Collapse
|
11
|
[Kratom - a short review for pain medicine]. Schmerz 2021; 36:128-134. [PMID: 34533652 PMCID: PMC8447806 DOI: 10.1007/s00482-021-00588-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/12/2021] [Indexed: 11/18/2022]
Abstract
Hintergrund Der Konsum des psychotrop wirksamen Kratoms (botanischer Name: Mitragyna speciosa) erfolgt teilweise zum Zweck der Selbstmedikation bei chronischen und akuten Schmerzen. Eine zunehmende Verbreitung des Konsums in Deutschland ist in Zukunft möglich. Ziele der Arbeit Diese Übersicht vermittelt daher Schmerztherapeuten pharmakologische Aspekte sowie Essenzielles zur psychischen Wirkung, zur Wirkung auf Schmerzen und zu den Risiken von Kratom, inkl. Abhängigkeit. Material und Methoden Es erfolgte eine strukturierte Literaturrecherche in PubMed bis Mitte Januar 2021. Wir fanden 426 relevante Literaturstellen. Acht davon beschäftigten sich spezifisch mit Kratom und Schmerz. Ergebnisse Neben weiteren Alkaloiden enthält Kratom das an Opioidrezeptoren wirksame (7-Hydroxy‑)Mitragynin. Der Konsum birgt Risiken, u. a. aufgrund nichtstandardisierter Verabreichung, aber auch durch direkte gesundheitliche Schäden bis hin zur möglichen Entwicklung einer Abhängigkeit. Diskussion Aktuell kann evidenzbasiert keine Empfehlung zur Nutzung von Kratom als Analgetikum gegeben werden. Für Schmerztherapeuten ist es wichtig, einen eventuellen Kratomkonsum zu erfragen und den Patienten über die potenziellen Risiken von Kratom zu informieren.
Collapse
|
12
|
Prozialeck WC, Lamar PC, Krupp M, Moon M, Phelps LE, Grundmann O. Kratom Use Within the Context of the Evolving Opioid Crisis and the COVID-19 Pandemic in the United States. Front Pharmacol 2021; 12:729220. [PMID: 34512353 PMCID: PMC8427750 DOI: 10.3389/fphar.2021.729220] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 08/12/2021] [Indexed: 12/18/2022] Open
Abstract
Kratom (Mitragyna speciosa, Korth.) is an evergreen tree that is indigenous to Southeast Asia. When ingested, kratom leaves or decoctions from the leaves have been reported to produce complex stimulant and opioid-like effects. For generations, native populations in Southeast Asia have used kratom products to stave off fatigue, improve mood, alleviate pain and manage symptoms of opioid withdrawal. Despite the long history of kratom use in Asia, it is only within the past 10-20 years that kratom has emerged as an important herbal agent in the United States, where it is being used for the self-treatment of pain, opioid withdrawal symptoms, and mood disorders. The increase in the use of kratom in the United States has coincided with the serious epidemic of opioid abuse and dependence. Since 2015, efforts to restrict access to prescription opioids have resulted in a marked increase in the use of "street" opioids such as heroin and illicit fentanyl. At the same time, many patients with chronic pain conditions or opioid use disorder have been denied access to appropriate medical help. The lack of access to care for patients with chronic pain and opioid use disorder has been magnified by the emergence of the COVID-19 pandemic. In this report, we highlight how these converging factors have led to a surge in interest in kratom as a potential harm reduction agent in the treatment of pain and opioid use disorder.
Collapse
Affiliation(s)
- Walter C Prozialeck
- Department of Pharmacology, Midwestern University, Downers Grove, IL, United States
| | - Peter C Lamar
- Department of Pharmacology, Midwestern University, Downers Grove, IL, United States
| | - Michael Krupp
- Department of Pharmacology, Midwestern University, Downers Grove, IL, United States
| | - Matthew Moon
- Department of Pharmacology, Midwestern University, Downers Grove, IL, United States
| | - Laura E Phelps
- Department of Pharmacology, Midwestern University, Downers Grove, IL, United States
| | - Oliver Grundmann
- Department of Medicinal Chemistry, College of Pharmacy, University of Florida, Gainesville, FL, United States
| |
Collapse
|
13
|
Hassan R, Sreenivasan S, Müller CP, Hassan Z. Methadone, Buprenorphine, and Clonidine Attenuate Mitragynine Withdrawal in Rats. Front Pharmacol 2021; 12:708019. [PMID: 34322028 PMCID: PMC8311127 DOI: 10.3389/fphar.2021.708019] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 06/29/2021] [Indexed: 11/13/2022] Open
Abstract
Background: Kratom or Mitragyna speciosa Korth has been widely used to relieve the severity of opioid withdrawal in natural settings. However, several studies have reported that kratom may by itself cause dependence following chronic consumption. Yet, there is currently no formal treatment for kratom dependence. Mitragynine, is the major psychoactive alkaloid in kratom. Chronic mitragynine treatment can cause addiction-like symptoms in rodent models including withdrawal behaviour. In this study we assessed whether the prescription drugs, methadone, buprenorphine and clonidine, could mitigate mitragynine withdrawal effects. In order to assess treatment safety, we also evaluated hematological, biochemical and histopathological treatment effects. Methods: We induced mitragynine withdrawal behaviour in a chronic treatment paradigm in rats. Methadone (1.0 mg/kg), buprenorphine (0.8 mg/kg) and clonidine (0.1 mg/kg) were i.p. administered over four days during mitragynine withdrawal. These treatments were stopped and withdrawal sign assessment continued. Thereafter, toxicological profiles of the treatments were evaluated in the blood and in organs. Results: Chronic mitragynine treatment caused significant withdrawal behaviour lasting at least 5 days. Methadone, buprenorphine, as well as clonidine treatments significantly attenuated these withdrawal signs. No major effects on blood or organ toxicity were observed. Conclusion: These data suggest that the already available prescription medications methadone, buprenorphine, and clonidine are capable to alleviate mitragynine withdrawal signs rats. This may suggest them as treatment options also for problematic mitragynine/kratom use in humans.
Collapse
Affiliation(s)
- Rahimah Hassan
- Centre for Drug Research, Universiti Sains Malaysia, Minden, Malaysia
| | - Sasidharan Sreenivasan
- Institute for Research in Molecular Medicine, Universiti Sains Malaysia, Minden, Malaysia
| | - Christian P Müller
- Centre for Drug Research, Universiti Sains Malaysia, Minden, Malaysia.,Section of Addiction Medicine, Department of Psychiatry and Psychotherapy, University Clinic, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany
| | - Zurina Hassan
- Centre for Drug Research, Universiti Sains Malaysia, Minden, Malaysia.,Addiction Behaviour and Neuroplasticity Laboratory, National Neuroscience Institute, Singapore, Singapore
| |
Collapse
|
14
|
Domnic G, Narayanan S, Mohana-Kumaran N, Singh D. Kratom (Mitragyna speciosa Korth.) an overlooked medicinal plant in Malaysia. JOURNAL OF SUBSTANCE USE 2021. [DOI: 10.1080/14659891.2021.1885515] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Gregory Domnic
- School of Biological Sciences, Universiti Sains Malaysia, Penang, Malaysia
| | - Suresh Narayanan
- School of Social Sciences, Universiti Sains Malaysia, Penang, Malaysia
| | | | - Darshan Singh
- Centre for Drug Research, Universiti Sains Malaysia, Penang, Malaysia
| |
Collapse
|
15
|
Vento AE, de Persis S, De Filippis S, Schifano F, Napoletano F, Corkery JM, Kotzalidis GD. Case Report: Treatment of Kratom Use Disorder With a Classical Tricyclic Antidepressant. Front Psychiatry 2021; 12:640218. [PMID: 33868054 PMCID: PMC8044355 DOI: 10.3389/fpsyt.2021.640218] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 03/05/2021] [Indexed: 12/13/2022] Open
Abstract
Kratom or Mitragyna speciosa (Korth.) is an evergreen tree of the coffee family native to South-East Asia and Australasia. It is used by locals recreationally to induce stimulant and sedative effects and medically to soothe pain and opiate withdrawal. Its leaves are smoked, chewed, or infused, or ground to yield powders or extracts for use as liquids. It contains more than 40 alkaloids; among these, mitragynine and 7-hydroxymitragynine are endowed with variable mu, delta, and kappa opioid stimulating properties (with 7-hydroxymitragynine having a more balanced affinity), rhynchophylline, which is a non-competitive NMDA glutamate receptor antagonist, but is present in negligible quantities, and raubasine, which inhibits α1-adrenceptors preferentially over α2-adrenceptors, while the latter are bound by 7-hydroxymitragynine, while mitragynine counters 5-HT2A receptors. This complexity of neurochemical mechanisms may account for kratom's sedative-analgesic and stimulant effects. It is commonly held that kratom at low doses is stimulant and at higher doses sedative, but no cut-off has been possible to define. Long-term use of kratom may produce physical and psychological effects that are very similar to its withdrawal syndrome, that is, anxiety, irritability, mood, eating, and sleep disorders, other than physical symptoms resembling opiate withdrawal. Kratom's regulatory status varies across countries; in Italy, both mitragynine and the entire tree and its parts are included among regulated substances. We describe the case of a patient who developed anxiety and dysphoric mood and insomnia while using kratom, with these symptoms persisting after withdrawal. He did not respond to a variety of antidepressant combinations and tramadol for various months, and responded after 1 month of clomipramine. Well-being persisted after discontinuing tramadol.
Collapse
Affiliation(s)
- Alessandro E Vento
- ASL (Azienda Sanitaria Locale) Roma 2, Rome, Italy.,Addictions' Observatory (ODDPSS), Rome, Italy
| | | | - Sergio De Filippis
- Villa von Siebenthal Neuropsychiatric Clinic and Hospital, Genzano di Roma, Italy
| | - Fabrizio Schifano
- Psychopharmacology, Drug Misuse & Novel Psychoactive Substances Research Unit, School of Life and Medical Sciences, University of Hertfordshire, Hatfield, United Kingdom
| | - Flavia Napoletano
- Psychopharmacology, Drug Misuse & Novel Psychoactive Substances Research Unit, School of Life and Medical Sciences, University of Hertfordshire, Hatfield, United Kingdom
| | - John M Corkery
- Psychopharmacology, Drug Misuse & Novel Psychoactive Substances Research Unit, School of Life and Medical Sciences, University of Hertfordshire, Hatfield, United Kingdom
| | - Georgios D Kotzalidis
- Villa von Siebenthal Neuropsychiatric Clinic and Hospital, Genzano di Roma, Italy.,NESMOS Department (Neurosciences, Mental Health, and Sensory Organs), School of Medicine and Psychology, Sant'Andrea Hospital, Sapienza University, Rome, Italy
| |
Collapse
|
16
|
Abstract
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.
Collapse
Affiliation(s)
- C Michael White
- University of Connecticut School of Pharmacy, Storrs, CT, and Department of Pharmacy, Hartford Hospital, Hartford, CT
| |
Collapse
|
17
|
Metastasio A, Prevete E, Singh D, Grundmann O, Prozialeck WC, Veltri C, Bersani G, Corazza O. Can Kratom ( Mitragyna speciosa) Alleviate COVID-19 Pain? A Case Study. Front Psychiatry 2020; 11:594816. [PMID: 33329145 PMCID: PMC7717955 DOI: 10.3389/fpsyt.2020.594816] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 10/27/2020] [Indexed: 01/14/2023] Open
Abstract
Among the symptoms of COVID-19 fever, general malaise, pain and aches, myalgia, fatigue, and headache can affect the quality of life of patients, even after the end of the acute phase of the infection and can be long lasting. The current treatment of these symptoms, also because COVID-19 patients have been asked not to use non-steroidal anti-inflammatory drugs (NSAIDs), in particular ibuprofen are often unsatisfactory. Among the above mentioned symptoms malaise and fatigue seem the most difficult to treat. In this case report we describe the use of kratom (Mitragyna speciosa) by a patient with confirmed COVID-19 infection. What we observed was a fast and sustained relieve of the above mentioned symptoms.
Collapse
Affiliation(s)
- Antonio Metastasio
- School of Life and Medical Sciences, University of Hertfordshire, Hatfield, United Kingdom.,NHS Camden and Islington Trust, London, United Kingdom
| | - Elisabeth Prevete
- Department of Medico-Surgical Sciences and Biotechnologies, Sapienza University of Rome, Rome, Italy
| | - Darshan Singh
- Centre for Drug Research, Universiti Sains Malaysia, Minden, Malaysia
| | - Oliver Grundmann
- Department of Medicinal Chemistry, College of Pharmacy, University of Florida, Gainesville, FL, United States
| | - Walter C Prozialeck
- Department of Pharmacology, Midwestern University, Downers Grove, IL, United States
| | - Charles Veltri
- Department of Pharmaceutical Sciences, Midwestern University, Glendale, AZ, United States
| | - Giuseppe Bersani
- Department of Medico-Surgical Sciences and Biotechnologies, Sapienza University of Rome, Rome, Italy
| | - Ornella Corazza
- School of Life and Medical Sciences, University of Hertfordshire, Hatfield, United Kingdom.,Department of Medico-Surgical Sciences and Biotechnologies, Sapienza University of Rome, Rome, Italy
| |
Collapse
|
18
|
Kratom from Head to Toe—Case Reviews of Adverse Events and Toxicities. CURRENT EMERGENCY AND HOSPITAL MEDICINE REPORTS 2019. [DOI: 10.1007/s40138-019-00194-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Abstract
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.
Collapse
|
19
|
Coe MA, Pillitteri JL, Sembower MA, Gerlach KK, Henningfield JE. Kratom as a substitute for opioids: Results from an online survey. Drug Alcohol Depend 2019; 202:24-32. [PMID: 31284119 DOI: 10.1016/j.drugalcdep.2019.05.005] [Citation(s) in RCA: 81] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 05/01/2019] [Accepted: 05/02/2019] [Indexed: 12/23/2022]
Abstract
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.
Collapse
Affiliation(s)
- Marion A Coe
- Research, Health Policy and Abuse Liability, Pinney Associates, Inc., 4800 Montgomery Lane, Suite 400, Bethesda, MD, 20814, USA.
| | - Janine L Pillitteri
- Pinney Associates, Inc., 201 North Craig Street, Suite 320, Pittsburgh, PA 15213, USA.
| | - Mark A Sembower
- Pinney Associates, Inc., 201 North Craig Street, Suite 320, Pittsburgh, PA 15213, USA.
| | - Karen K Gerlach
- Pinney Associates, Inc., 201 North Craig Street, Suite 320, Pittsburgh, PA 15213, USA.
| | - Jack E Henningfield
- Research, Health Policy and Abuse Liability, Pinney Associates, Inc., 4800 Montgomery Lane, Suite 400, Bethesda, MD, 20814, USA; Department of Psychiatry and Behavioral Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| |
Collapse
|
20
|
Veltri C, Grundmann O. Current perspectives on the impact of Kratom use. Subst Abuse Rehabil 2019; 10:23-31. [PMID: 31308789 PMCID: PMC6612999 DOI: 10.2147/sar.s164261] [Citation(s) in RCA: 80] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Accepted: 06/07/2019] [Indexed: 12/15/2022] Open
Abstract
The leaves from the tree Mitragyna speciosa, commonly known as Kratom, in the coffee plant family (Rubiaceae) are commonly used in their native habitat of Southeast Asia as a stimulant to sustain energy during hard day labor and as an opioid-like analgesic and sedative. Traditional and modern uses overlap based on the effects of the leaf extract which has also gained popularity in the United States and Europe in the last two decades. Kratom has and is being used for the mitigation of opioid withdrawal symptoms and as a harm reduction agent with a minority of users subsequently developing a dependence on the extract. The respective demographic use patterns of Kratom differ between Southeast Asia and the Western world. While pure Kratom is primarily used by day laborers and misused in conjunction with cough medicine by youth in Southeast Asia, a majority of users in the United States is middle-aged, has at least middle income, private health insurance, and completed some college. Deaths attributed to the use of Kratom have been reported in Europe and the United States but not in Southeast Asia. Although Kratom was detected as the alkaloid mitragynine in the blood of the decedents, causality could not be established in almost all cases because of poly-drug exposures. It is notable that Kratom can cause herb–drug interactions, especially with other central nervous system -active substances. Given the mostly unregulated market for Kratom products in Western countries, consumers may be exposed to adulterated or contaminated products, especially if purchased through websites or the darknet. A number of countries have scheduled Kratom because of its stimulant- and opioid-like effects and the established interaction of the alkaloid mitragynine with opioid receptors.
Collapse
Affiliation(s)
- Charles Veltri
- Department of Pharmaceutical Sciences, College of Pharmacy, Midwestern University, Glendale, AZ 85308, USA
| | - Oliver Grundmann
- Department of Pharmaceutical Sciences, College of Pharmacy, Midwestern University, Glendale, AZ 85308, USA.,Department of Medicinal Chemistry, College of Pharmacy, University of Florida, Gainesville, FL, 32611, USA
| |
Collapse
|
21
|
Eldridge WB, Foster C, Wyble L. Neonatal Abstinence Syndrome Due to Maternal Kratom Use. Pediatrics 2018; 142:peds.2018-1839. [PMID: 30404789 DOI: 10.1542/peds.2018-1839] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/09/2018] [Indexed: 12/17/2022] Open
Abstract
Neonatal abstinence syndrome (NAS) is increasing in incidence and most commonly associated with maternal opioid use during pregnancy. Nonopioid alternatives to treat opioid dependence are highly sought after in the country's current opioid epidemic. Whether Kratom, a legal, widely available herbal supplement, should be classified as an opioid is contentious. Although the US Food and Drug Administration has recently addressed this controversy, Kratom continues to be marketed as a nonopioid remedy for opioid withdrawal. Its use is increasing in the United States. We describe an infant with NAS born to a mother with daily Kratom tea ingestion to self-treat opioid dependence. Pediatricians and parents should be aware of the risk of NAS due to Kratom use during pregnancy.
Collapse
|
22
|
Singh D, Narayanan S, Müller CP, Swogger MT, Rahim AA, Leong Bin Abdullah MFI, Vicknasingam BK. Severity of Kratom (Mitragyna speciosa Korth.) Psychological Withdrawal Symptoms. J Psychoactive Drugs 2018; 50:445-450. [PMID: 30152738 DOI: 10.1080/02791072.2018.1511879] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
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.
Collapse
Affiliation(s)
- Darshan Singh
- a Center for Drug Research , Universiti Sains Malaysia , Penang , Malaysia
| | - Suresh Narayanan
- b School of Social Sciences , Universiti Sains Malaysia , Penang , Malaysia
| | - Christian P Müller
- c Department of Psychiatry and Psychotherapy , University Clinic, Friedrich-Alexander-University Erlangen-Nuremberg , Erlangen , Germany
| | - Marc T Swogger
- d Department of Psychiatry , University of Rochester Medical Center , Rochester , NY, USA
| | - Azlan Abdul Rahim
- a Center for Drug Research , Universiti Sains Malaysia , Penang , Malaysia
| | | | | |
Collapse
|