Kratom (Mitragyna speciosa): eine psychoaktive Pflanze mit Chancen und Risiken

Zusammenfassung

Kratom ist ein immergrüner Baum, der in Südostasien heimisch ist und dessen Blätter traditionell als Stimulans, als Therapie bei verschiedenen gesundheitlichen Problemen und zu religiösen Zwecken verwendet werden. Insbesondere in den USA (geringer auch in Europa) wird seit einigen Jahren eine relevante Prävalenz des Kratomkonsums beobachtet. In westlichen Ländern wird Kratom überwiegend als Analgetikum und Stimulans, zur Behandlung von Schmerzen und Opioidgebrauchsstörungen und zur günstigen Beeinflussung der psychischen Gesundheit (z. B. bei Depression, Angststörungen) verwendet. Die chemischen Hauptbestandteile von Kratom sind Alkaloide, von denen Mitragynin und 7-Hydroxymitragynin am bedeutsamsten erscheinen. Die Pharmakodynamik und -kinetik von Kratom sind komplex und unzureichend untersucht. Bekannt ist, dass Mitragynin und 7-Hydroxymitragynin Partialagonisten an humanen μ-Opioidrezeptoren und Antagonisten an κ- und δ-Opioidrezeptoren bei zusätzlichen Effekten an weiteren zentralen Rezeptoren sind. Die Verträglichkeit von Kratom scheint im Vergleich mit klassischen Opioiden besser zu sein, was mit fehlenden Effekten von Kratom auf β-Arrestin in Verbindung gebracht und als Ausgangspunkt für die Entwicklung besser verträglicher Opioide diskutiert wurde. Einige Alkaloide in Kratom sind Inhibitoren von CYP2D6, geringer auch CYP2C19 und CYP3A4. Das Abhängigkeitspotential von Kratom scheint geringer ausgeprägt zu sein als das von klassischen Opioiden, wobei die Datenlage dazu begrenzt ist und Kratomgebrauchsstörungen primär in westlichen Längern auftreten. Es sind zahlreiche Fälle von schwerwiegenden gesundheitlichen Problemen und Todesfälle im Zusammenhang mit Kratomkonsum in den USA bekannt, wobei in diesen Fällen meist mehrere Substanzen involviert waren. Kratomkonsum ist vermutlich mit hepatotoxischen und kardiotoxischen Effekten assoziiert. Kratom-assoziierte Morbidität und Mortalität unterscheiden sich zwischen westlichen Ländern und Südostasien, wo Kratomkonsum kein öffentliches Gesundheitsproblem darstellt, quantitativ erheblich. Als Gründe hierfür wurden der in westlichen Ländern verbreitete Mischkonsum, höhere Dosierungen konsumierten Kratoms, Verfälschungen und Verunreinigungen kommerziell erhältlicher Kratomprodukte in westlichen Ländern, pharmakokinetische Interaktionen und höhere Konzentrationen von 7-Hydroxymitragynin in getrockneten Kratomblättern (die typischerweise in westlichen Ländern konsumiert werden) im Vergleich mit frischen Blättern (die typischerweise in Südostasien konsumiert werden) genannt.

Abstract

Kratom is an evergreen tree that is native to Southeast Asia. Its leafs are traditionally used as a stimulant, a remedy for various health problems and for religious purposes. Especially in the US (in a lesser extent also in Europe) kratom use is significantly prevalent. In Western countries, kratom is used predominantly as an analgesic and stimulant, for the treatment of opioid use disorders, and for improving mental health (e. g., in depression, anxiety disorders). Main molecular constituents of kratom are alkaloids of which mitragynine and 7-hydroxymitragynine appear to be most important. Pharmacodynamics and -kinetics of kratom are complex and insufficiently studied. It is known that mitragynine and 7-hydroxymitragynine are partial agonist at human μ-opioid receptors and antagonists at κ- and δ-opioid receptors with additional effects at other central receptors. Tolerability of kratom is presumably better than that of classical opioids; this is probably due to missing effects of kratom on β-arrestin and discussed as a starting point for the development of opioids with improved tolerability. Some alkaloids of kratom are inhibitors of CYP26 and to a somewhat lesser degree of CYP2C19 and CYP3A4. The addictive potential of kratom appears to be lower than that of classical opioids; however, corresponding data is limited and kratom use disorders appear to occur primarily in Western countries. Several cases of severe health-related problems and deaths are known in the US; in these cases, however, polysubstance use was usually present. Kratom use is likely associated with hepatotoxicity and cardiotoxicity. Kratom-associated mortality and morbidity in Western countries are quantitatively significantly different from Southeast Asia, where kratom use is no public health problem. The reasons for this may be the combined use of substances (which is more prevalent in Western countries), higher dosages of consumed kratom, adulterations and contaminations of commercially available kratom in Western countries, pharmacokinetic interactions, and higher concentrations of 7-hydroxymitragynine in dried kratom leafs (that are typically consumed in Western countries) in comparison to fresh leafs (that are typically consumed in Southeast Asia).

Schlüsselwörter

legal high - Opioidabhängigkeit - Opioidgebrauchsstörung - Schmerzstörung

Key words

legal high - opioid dependence - opioid use disorder - pain disorder

Publication History

Received: 07 January 2022

Accepted after revision: 11 April 2022

Article published online:
25 May 2022

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