Seizure-like movements during a fentanyl infusion with absence of seizure activity in a simultaneous EEG recording

Abstract

We report the absence of cortical seizure activity in an EEG recording during an apparent 'seizure' observed in a 73-year-old man receiving a fentanyl infusion. The peak fentanyl serum concentration was 32.0 ng/ml. We attribute this abnormal motor activity either to myoclonus produced by narcotic depression of higher central nervous system inhibitory centers or to a pronounced form of narcotic-induced rigidity.