Kratom Pharmacology and Opioid Use Disorders

Kratom, derived from the Southeast Asian tree Mitragyna speciosa, contains a complex mixture of indole alkaloids that interact with opioid and non-opioid receptors. The primary constituents, mitragynine and 7-hydroxymitragynine, act as partial agonists at the μ-opioid receptor and exhibit biased signalling, favouring G-protein pathways with minimal β-arrestin recruitment. This profile underpins kratom’s analgesic effects and its historical use to alleviate opioid withdrawal. Pharmacokinetic studies reveal stereochemical influences on absorption, distribution and clearance, while in vitro assays demonstrate inhibition of key cytochrome P450 enzymes, raising concerns over drug–herb interactions. Clinically, kratom use may fulfil DSM-5 criteria for a substance use disorder, typically driven by tolerance and withdrawal rather than psychosocial disruption. Globally, the botanical is both lauded for potential harm-reduction in opioid dependence and scrutinised for safety, with regulatory approaches varying widely. Ongoing research seeks to standardise alkaloid production, clarify dose–response relationships and develop evidence-based treatment algorithms for kratom use disorder.

Research from Nature Portfolio

Comprehensive metabolomic profiling of commercial kratom products has identified two distinct chemotypes, differentiated by spe­ciofoline content. Functional assays reveal that mitragynine and 7-hydroxymitragynine are partial μ-opioid agonists with G-protein bias and negligible β-arrestin recruitment, whereas speciofoline lacks measurable opioid receptor affinity. These studies further show that major alkaloids inhibit select cytochrome P450 isoforms, indicating a potential for adverse pharmacokinetic interactions when kratom is co-consumed with other medications. The work underscores the need to characterise chemotype variability when assessing both therapeutic potential and safety.

Kratom Pharmacology and Opioid Use Disorders publication trend

The graph below shows the total number of articles in kratom pharmacology and opioid use disorders across all publications each year (not limited to Nature Index journals).

Technical terms

Alkaloid: A naturally occurring nitrogenous compound in plants, often with significant pharmacological activity.

μ-Opioid receptor: A G-protein-coupled receptor that mediates analgesia and reward upon activation by endogenous peptides or exogenous agonists.

Biased agonism: The preferential activation of one intracellular signalling pathway (e.g. G-protein) over another (e.g. β-arrestin) by a ligand.

Cytochrome P450 enzymes: A family of liver microsomal enzymes responsible for oxidative metabolism of xenobiotics and endogenous compounds.

Stereoisomer: One of two or more compounds with the same molecular formula and connectivity but differing three-dimensional orientations.

References

1. Directed Biosynthesis of Mitragynine Stereoisomers. Journal of the American Chemical Society (2023).
2. Controversies in Assessment, Diagnosis, and Treatment of Kratom Use Disorder. Current Psychiatry Reports (2024).
3. Chemical composition and biological effects of kratom (Mitragyna speciosa): In vitro studies with implications for efficacy and drug interactions. Scientific Reports (2020).
4. Evaluation of the Effects of Mitragyna speciosa Alkaloid Extract on Cytochrome P450 Enzymes Using a High Throughput Assay. Molecules (2011).
5. Clinical Pharmacokinetic Assessment of Kratom (Mitragyna speciosa), a Botanical Product with Opioid-like Effects, in Healthy Adult Participants. Pharmaceutics (2022).