Naphyrone toxicity

Objective: To assess the severity and diversity of symptoms associated with exposure to naphyrone, a recreational cathinone. Methods: Records of enquiries to the UK National Poisons Information Service (NPIS) for the period April 2009 to October 2010 relating to naphyrone exposure were retrospectively reviewed and analysed. Results: In the 56 telephone enquiries received throughout the study period, the most frequently reported symptoms were tachycardia (in 21% of cases), and agitation (19%). Anxiety, somnolence and chest pain were each associated with 11% of enquiries. Other features observed included hallucinations, nausea and vomiting, palpitations, paranoia, visual disturbances and a raised temperature. In four cases raised serum creatine kinase was observed, the highest recorded being 3070 U/L. The severity score for the majority of exposures (55%) was considered to be minor with 28% reported as moderate. One patient was reported as severe, suffering a cardiac arrest en route to hospital, he subsequently died of respiratory failure following complications from inhaling gastric contents and underlying emphysema. Cause of death was not recorded as exposure to naphyrone. The youngest patient reported was 14 years old; 38% of patients were less than 20 years, 43% between the ages of 21 and 40 years, 11% were over 40 years and 8% were of adult age unknown. The most commonly reported route of exposure was ingestion (73%) - other routes included inhalation (12%), injection (3%) and unknown (12%); a few cases reported multiple routes of exposure. Most cases (81%) involved exposure to naphyrone alone, in ten cases there was a single co-ingestant and one patient was also exposed to mephedrone, cocaine and alcohol. Conclusion: The NPIS regularly receives enquiries regarding new or emerging drugs of abuse. While the symptoms seen with this particular drug appear to be minor in most cases, some patients experience moderate or potentially life threatening toxicity. The number of naphyrone enquiries increased rapidly following the classification of mephedrone as a Class B drug in April 2010. In July 2010 naphyrone was also classified as a Class B drug - increased vigilance is required as other substances of unknown toxicity seek to fill this new gap in the market.