The Tox Lab

Episode 78: Strange Things in Strange Places – Poison Dart Frogs, Navalny and Epibatidine

This week on The Tox Lab, we’re discussing poison dart frogs and the alkaloid epibatidine. We begin by examining recent reports surrounding the death of Alexei Navalny and the suggestion that epibatidine may have been involved. We then discuss poison dart frogs and the toxins found within them, including the discovery and isolation of epibatidine. From there, we explore its potent analgesic properties, how it acts at nicotinic acetylcholine receptors, and what makes it both pharmacologically interesting and highly toxic. Finally, we examine attempts to develop epibatidine analogues as novel analgesics and explore the evolutionary question of how poison dart frogs themselves avoid poisoning. Join us as we examine the pharmacology, toxicity, and evolving story surrounding epibatidine, and consider how a toxin derived from poison dart frogs became linked to drug development, toxicology, and international headlines. Hope you enjoy! Links to the papers we discussed: https://www.gov.uk/government/news/joint-statement-by-the-uk-sweden-france-germany-and-the-netherlands-on-alexei-navalnys-death https://pubs.rsc.org/en/content/articlelanding/2000/np/a900728h https://www.science.org/doi/epdf/10.1126/science.aan5061 Check out our new website: https://thetoxlab.co.uk/ Disclaimer: All opinions are our own. Find us on instagram: @the_tox_lab Email us here: thetoxlab@gmail.com Support us here: https://buymeacoffee.com/thetoxlab

Episode 77: Novel Synthetic Opioids – An Update on Emerging Trends

This week on The Tox Lab, we’re back with a long-awaited update on novel synthetic opioids. We begin by discussing the April 2026 UNODC announcement on the increasingly varied forms in which synthetic opioids are being encountered, including vapes, powders, and counterfeit tablets marketed as benzodiazepines, oxycodone, and MDMA. We then turn to the emergence of orphine analogues in both the UK and the US, discussing recent reports and trends associated with these compounds. Finally, we examine a clinical case involving N-propionitrile chlorphine (cychlorphine), exploring the toxicological features and the challenges these emerging opioids present for clinicians, laboratories, and public health systems. Join us as we examine the changing landscape of novel synthetic opioids, consider what these developments may mean for toxicology, harm reduction, and public health, and discuss where the market may be heading next. Hope you enjoy! This episode is very kindly sponsored by Cayman Chemical. Check out their Synthetic Opioid Analytical Standards Panel here: https://www.caymanchem.com/product/44436/synthetic-opioid-analytical-standards-panel-1 Links to papers we discussed: https://www.unodc.org/LSS/Announcement/Details/973e194e-f8d6-4b4e-8aca-166aaec4ac7c https://www.polizei.bayern.de/aktuelles/pressemitteilungen/100413/index.html https://onlinelibrary.wiley.com/doi/10.1111/dar.70081 https://assets.publishing.service.gov.uk/media/69f3343fab602a88957eef2b/Seventh_addendum_to_the_ACMD_report_on_the_use_and_harms_of_2-benzyl-benzimidazole__nitazene__and_piperidine_benzimidazolone__brorphine-like__opioids_FINAL.pdf https://www.cfsre.org/nps-discovery/public-alerts/increase-in-fatal-overdoses-linked-to-novel-synthetic-opioid-n-propionitrile-chlorphine-cychlorphine https://www.tandfonline.com/doi/full/10.1080/15563650.2025.2594070 Link to our paper on N-pyrrolidino Isotonitazene: https://academic.oup.com/jat/advance-article-abstract/doi/10.1093/jat/bkag027/8663758?redirectedFrom=fulltext Disclaimer: All opinions are our own. Find us on instagram: @the_tox_lab Email us here: thetoxlab@gmail.com Support us here: https://buymeacoffee.com/thetoxlab

Episode 76: Naloxone - Access, Harm Reduction and Disparities

This week on The Tox Lab, we are taking a look at the role of naloxone in risk taking behaviours, harm reduction and disparities surrounding naloxone access. We begin by discussing a study looking at the expansion of naloxone access laws in the United States, exploring whether increased availability is associated with changes in heroin use among adolescents. We then turn to a commentary paper examining the benefits and limitations of educating school children recognise an opioid overdose and administer naloxone. Finally we discuss a paper investigating disparities in naloxone uptake amongst different ethnic and racial groups, and between individuals who inject versus smoke substances. Join us as we explore the impact of naloxone access, education, and disparities, and consider what these findings mean for harm reduction and public health. Hope you enjoy! Links to the papers we discussed: https://www.sciencedirect.com/science/article/abs/pii/S0955395923000294 https://onlinelibrary.wiley.com/doi/abs/10.1111/josh.70089 https://pubmed.ncbi.nlm.nih.gov/41428846/ Disclaimer: All opinions are our own. Find us on instagram: @the_tox_lab Email us here: thetoxlab@gmail.com Support us here: https://buymeacoffee.com/thetoxlab

Episode 75: Kratom Is Changing - New Semi-Synthetic Compounds & Rising Harm

A year after we first took a look at mitragynine (kratom), we are back with an update episode looking at how the landscape surrounding mitragynine is evolving. We begin by examining poison centre data, exploring trends in reported exposures in the US and internationally, and the increase in its use. We then discuss a case involving semi-synthetic mitragynine derivatives, including 7-hydroxymitragynine and mitragynine pseudoindoxyl, highlighting the clinical features including dose escalation, and challenges associated with withdrawal. Finally, we turn to reports of combined use of kratom and kava, and consider how this may influence toxicity and withdrawal. Join us as we examine emerging data, evolving patterns of use, and the clinical implications of mitragynine and its derivatives, and consider what these findings mean for toxicology and public health. Hope you enjoy! If you'd like us to cover an episode on Kava, please let us know in the comments! Links to the papers we discussed: https://www.cdc.gov/mmwr/volumes/75/wr/mm7511a1.htm https://www.cureus.com/articles/467977-severe-early-onset-withdrawal-following-intentional-use-of-mitragynine-pseudoindoxyl-a-case-report-and-emerging-clinical-considerations#!/ https://www.cdc.gov/mmwr/volumes/75/wr/pdfs/mm7512a1-H.pdf https://journals.lww.com/journaladdictionmedicine/abstract/9900/kava_potentiated_withdrawal_in_persons_using.687.aspx Disclaimer: All opinions are our own. Find us on instagram: @the_tox_lab Email us here: thetoxlab@gmail.com Support us here: https://buymeacoffee.com/thetoxlab

Episode 74: Codeine – Pharmacogenetics, Breastfeeding and the 2006 Lancet Case

This week on The Tox Lab, we’re examining the controversial 2006 Lancet paper on codeine and fatal opioid toxicity in a breastfed infant. We begin by introducing the paper and the case at its centre, in which an infant developed fatal opioid toxicity following exposure to codeine via breast milk. We then explore the proposed mechanism, focusing on the role of CYP2D6 metabolism and how variability in this pathway may lead to higher-than-expected morphine concentrations. We also discuss the limitations and criticisms of the paper, including questions around causality, alternative explanations, and the extent to which pharmacogenetics alone can account for the outcome. Finally, we consider the wider impact of this publication, including changes to clinical guidance, prescribing practices, and the ongoing debate around codeine use in breastfeeding individuals. Join us as we examine the pharmacology, pharmacogenetics, and controversy surrounding this landmark case, and consider what this means for clinical toxicology and patient safety. Hope you enjoy! Links to the papers we discussed: https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(06)69255-6/abstract https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(26)00245-X/fulltext https://www.thelancet.com/journals/lancet/article/PIIS0140673608612544/abstract https://ascpt.onlinelibrary.wiley.com/doi/10.1002/cpt.1882 Link to the New Yorker Article : https://www.newyorker.com/magazine/2026/02/02/did-a-celebrated-researcher-obscure-a-fatal-poisoning Disclaimer: All opinions are our own. Find us on instagram: @the_tox_lab Email us here: thetoxlab@gmail.com Support us here: https://buymeacoffee.com/thetoxlab