Five percent CO₂ is a potent, fast-acting inhalation anticonvulsant.

Journal Article (Journal Article)

PURPOSE: CO₂ has been long recognized for its anticonvulsant properties. We aimed to determine whether inhaling 5% CO₂ can be used to suppress seizures in epilepsy patients. The effect of CO₂ on cortical epileptic activity accompanying behavioral seizures was studied in rats and nonhuman primates, and based on these data, preliminary tests were carried out in humans. METHODS:   In freely moving rats, cortical afterdischarges paralleled by myoclonic convulsions were evoked by sensorimotor cortex stimulation. Five percent CO₂ was applied for 5 min, 3 min before stimulation. In macaque monkeys, hypercarbia was induced by hypoventilation while seizure activity was electrically or chemically evoked in the sensorimotor cortex. Seven patients with drug-resistant partial epilepsy were examined with video-EEG (electroencephalography) and received 5% CO₂ in medical carbogen shortly after electrographic seizure onset. RESULTS: In rats, 5% CO₂ strongly suppressed cortical afterdischarges, by approximately 75%, whereas responses to single-pulse stimulation were reduced by about 15% only. In macaques, increasing pCO₂) from 37 to 44-45 mm Hg (corresponding to inhalation of 5% CO₂ or less) suppressed stimulation-induced cortical afterdischarges by about 70% and single, bicuculline-induced epileptiform spikes by approximately 25%. In a pilot trial carried out in seven patients, a rapid termination of electrographic seizures was seen despite the fact that the application of 5% CO₂ was started after seizure generalization. CONCLUSIONS: Five percent CO₂ has a fast and potent anticonvulsant action. The present data suggest that medical carbogen with 5% CO₂ can be used for acute treatment to suppress seizures in epilepsy patients.

Full Text

Duke Authors

Cited Authors

  • Tolner, EA; Hochman, DW; Hassinen, P; Otáhal, J; Gaily, E; Haglund, MM; Kubová, H; Schuchmann, S; Vanhatalo, S; Kaila, K

Published Date

  • January 2011

Published In

Volume / Issue

  • 52 / 1

Start / End Page

  • 104 - 114

PubMed ID

  • 20887367

Pubmed Central ID

  • PMC3017646

Electronic International Standard Serial Number (EISSN)

  • 1528-1167

Digital Object Identifier (DOI)

  • 10.1111/j.1528-1167.2010.02731.x


  • eng

Conference Location

  • United States