Alfentanil-induced epileptiform activity: a simultaneous surface and depth electroencephalographic study in complex partial epilepsy.
OBJECTIVE
Alfentanil is a high potency mu opiate receptor agonist commonly used during presurgical induction of anesthesia. This and other opiate receptor agonists have demonstrated proconvulsant effects in animals, but these properties have been less consistently demonstrated in humans. Most human scalp EEG studies have failed to demonstrate induction of epileptiform activity with these agents, which is inconsistent with findings using intracranial EEG. Simultaneous scalp and depth EEG recordings have yet to be performed in this setting. The relationship between opiate dose and proconvulsant activity is unclear.


METHODS
Simultaneous scalp and depth electrode recordings were performed on five patients with complex partial epilepsy (CPE) who underwent alfentanil anesthesia induction before depth electrode removal. Consecutive equal bolus doses of alfentanil were administered to each patient according to strict time intervals so as to assess their correlation with any induced epileptiform activity.


RESULTS
Epileptiform activity was induced by alfentanil in three of five patients. Two of these patients had electrographic seizures. Epileptiform activity was only detected from the depth electrodes, occurring within 2 min of the first bolus dose in all three cases. Further increase or spread of epileptiform activity did not occur despite cumulative bolus doses of alfentanil.


CONCLUSIONS
Alfentanil is proconvulsant in patients with CPE. Induced seizures may be subclinical and lack a scalp EEG correlate. There is a complex dose-response relationship. Alfentanil induction of anesthesia should be approached with caution in patients with CPE.
Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, U.S.A. jels@massmed.org
J
J
Ross
L A
LA
Kearse
M K
MK
Barlow
K J
KJ
Houghton
G R
GR
Cosgrove
D000328:Adult; D015760:Alfentanil / Q000009:adverse effects / Q000494:pharmacology*; D000768:Anesthesia, General / Q000009:adverse effects; D018686:Anesthetics, Intravenous / Q000009:adverse effects / Q000494:pharmacology*; D001921:Brain / Q000187:drug effects / Q000503:physiopathology / Q000601:surgery; D020878:Device Removal; D004305:Dose-Response Relationship, Drug; D004567:Electrodes, Implanted; D004569:Electroencephalography / Q000187:drug effects* / Q000706:statistics & numerical data; D017029:Epilepsy, Complex Partial / Q000139:chemically induced* / Q000175:diagnosis / Q000503:physiopathology; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008297:Male; D013702:Temporal Lobe / Q000187:drug effects / Q000503:physiopathology
D018686:Anesthetics, Intravenous; D015760:Alfentanil