Prolonged Stupor in Perampanel Overdose and Pharmacokinetic Considerations.

Perampanel is a new antiepileptic drug with a long half-life, but there are currently no data on the effects of acute perampanel overdose in epilepsy patients. We report a patient who had such an overdose. A 39-year-old woman was admitted for altered consciousness after taking 10 times the daily dose of perampanel. Her blood level of the drug was predicted, by pharmacokinetic calculation, to decrease to a steady-state level after 7 days, followed by a full recovery 8 days after the overdose. During her hospital stay, the patient experienced pulmonary embolism, which may be associated with the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) antagonistic mechanism of perampanel. The present findings show that perampanel overdose can produce prolonged stupor and that caution should be exercised during transient hypercoagulable states.