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Case report
Prolonged unconsciousness in perampanel overdose
  1. Guy Parsons1,2,
  2. Jon Bailey1,
  3. Frederick Bailey1 and
  4. Max Brzezicki1
  1. 1 Critical Care, Milton Keynes University Hospital NHS Foundation Trust, Milton Keynes, UK
  2. 2 Nuffield Department of Clinical Neurosciences, Oxford University, Oxford, UK
  1. Correspondence to Dr Guy Parsons; guy.parsons{at}


Clinical experience of perampanel overdoses is markedly limited and the relevant literature is sparse. Perampanel is a novel antiepileptic drug (an amino-3-hydroxy-5-methyl-4-isoxazlepropionic acid glutamate receptor antagonist) with a long half-life, which is used for the adjunctive treatment of epilepsy. The literature available identifies a potential for prolonged unconsciousness in overdose. We report a case of prolonged unconsciousness for 14 days following a perampanel overdose of 3.5 times the maximum daily dose, requiring protracted intubation and ventilation on intensive care, with eventual complete neurological recovery. This represents the longest known period of unconsciousness with full recovery and the first reported in a perampanel naïve patient. This case helps to inform decision-making in critical care, particularly the early consideration of admission and intubation. It highlights that while perampanel overdose may not initially cause systemic effects such as cardiac toxicity, it can cause protracted altered consciousness with secondary compromise requiring prolonged intensive care management.

  • drugs: CNS (not psychiatric)
  • epilepsy and seizures
  • intensive care
  • mechanical ventilation
  • neurology (drugs and medicines)

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  • Contributors GP led the development of the manuscript from conception to submission, identifying areas of focus and the overall narrative as well as being involved at all stages of data acquisition and analysis. He was also engaged directly with the care of the patient involved. He led the revisions made to the text in response to the reviewers’ comments with the consent of the other authors. JB assisted with the original drafting of the manuscript and multiple subsequent revisions and was directly engaged with the care of the patient involved. FB and MB assisted with data acquisition, analysis and literature review for this manuscript and were both involved with the patient’s clinical care.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Patient consent for publication Obtained.

  • Provenance and peer review Not commissioned; externally peer reviewed.