PHARMACOEPIDEMIOLOGY AND PRESCRIPTION Acute toxicity associated with the recreational use of the ketamine derivative methoxetamine David M. Wood & Susannah Davies & Malgorzata Puchnarewicz & Atholl Johnston & Paul I. Dargan Received: 25 October 2011 /Accepted: 9 December 2011 /Published online: 29 December 2011 # Springer-Verlag 2011 Abstract Purpose Long-term regular use of ketamine has been reported to be associated with severe symptomatic urinary tract problems. Methoxetamine, an arylcyclohexylamine de- rivative of ketamine, is marketed as a “bladder safe” deriv- ative of ketamine, and no cases of acute toxicity following analytically confirmed methoxetamine use have been reported to date. We report here a case series of three individuals with acute toxicity related to the analytically confirmed use of methoxetamine. Case series Three patients aged between 28 and 42 years presented to the Emergency Department (ED) on unrelated occasions having used methoxetamine. Clinical features were suggestive of a “dissociative/catatonic” state similar to that seen with ketamine; in addition, they had clinical features of acute sympathomimetic toxicity with significant tachycardia and hypertension. All were managed with low- dose benzodiazepines and discharged home once their symptoms/signs had settled. Toxicological screening Serum collected at the time of pre- sentation to the ED was analysed qualitatively and quanti- tatively by gas chromatography–mass spectrometry. Serum concentrations ranged from 0.09 to 0.2 mg/L; in addition, detectable levels of 6-APB/5-APB were found in one of the patients. Conclusions These three analytically confirmed cases dem- onstrate that acute methoxetamine-related toxicity is associ- ated with both “dissociative” and “sympathomimetic” clinical features. The information from these three cases is useful to clinical pharmacologists, not only in managing individuals with acute methoxetamine toxicity but also in advising the appropriate legislative authorities on the risk of acute harm related to methoxetamine use. Further work is needed to determine whether methoxetamine is more “bladder friendly” than ketamine, as has been suggested by those marketing methoxetamine. Keywords Methoxetamine . Ketamine . Acute toxicity . Recreational drug Introduction Recreational use of ketamine is common throughout Europe and the USA [1, 2]. In addition to the risks of acute DW and PD have acted as scientific advisors to the UK Advisory Council on the Misuse of Drugs (ACMD) and the European Monitoring Centre for Drugs and Drug Addiction (EMCDDA). D. M. Wood : P. I. Dargan Clinical Toxicology, Guy’ s and St Thomas’ NHS Foundation Trust and Kings Health Partners, London, UK D. M. Wood : P. I. Dargan King’ s College London, London, UK D. M. Wood (*) Medical Toxicology Office, Guy’ s Hospital, 2nd Floor, Bermondsey Wing, Great Maze Pond, London SE1 9RT, UK e-mail: david.wood@gstt.nhs.uk S. Davies : M. Puchnarewicz Analytical Services International Ltd, St George’ s, University of London, London, UK A. Johnston Clinical Pharmacology, Barts and The London School of Medicine and Dentistry, Queen Mary, University of London, London, UK Eur J Clin Pharmacol (2012) 68:853–856 DOI 10.1007/s00228-011-1199-9