Dantrolene is not the answer to 2,4-dinitrophenol poisoning: more heated debate.

There has been a resurgence in the use of 2,4-dinitrophenol, C6H4N2O5 (DNP) recently as an illegal weight loss drug. We present a case of a healthy 25-year-old girl who took two tablets of DNP, purchased from an overseas online retailer. She was managed with aggressive, invasive cooling measures and 2.5 mg kg-1 dantrolene. Despite this, her temperature continued to rise exponentially to 41.5°C. Cardiac arrest occurred and resuscitation was unsuccessful. To our knowledge, this is the first reported case of the ineffective use of dantrolene in acute DNP poisoning. We review the pathophysiology of DNP toxicity and argue that the use of dantrolene therapy is biochemically implausible, based on poor evidence and likely to be futile. We have contacted the UK National Poisons Information Service (NPIS/TOXBASE) to propose changes to the management of acute DNP toxicity. © BMJ Publishing Group Limited 2018. No commercial re-use. See rights and permissions. Published by BMJ.