Psychopharmacology

, Volume 146, Issue 2, pp 180–184

Assessment of GABAA benzodiazepine receptor (GBzR) sensitivity in patients on benzodiazepines

  • J. Potokar
  • Nick Coupland
  • S. Wilson
  • A. Rich
  • David Nutt
Original Investigation

DOI: 10.1007/s002130051104

Cite this article as:
Potokar, J., Coupland, N., Wilson, S. et al. Psychopharmacology (1999) 146: 180. doi:10.1007/s002130051104

Abstract 

Objectives: To measure GABAA benzodiazepine receptor sensitivity in patients taking benzodiazepines and compare with matched controls. Methods: Seven patients who were on prescribed benzodiazepines for an anxiety disorder or insomnia were recruited from general practice and an adult mental health service outpatient clinic. They were matched with seven volunteers. All subjects received an intravenous injection of midazolam 50 µg/kg in 10 ml normal saline over 10 min. Objective responses to midazolam were assessed using saccadic eye movement velocity slowing and subjective assessments using visual analogue scales. Measurements were recorded for 120 min and plasma midazolam concentrations obtained at 15-min intervals post-infusion to 120 min. Ratios of pharmacodynamic/pharmacokinetic effects were obtained for each individual to estimate GABAA benzodiazepine receptor sensitivity. Results: Patients had an attenuated response to midazolam on both subjective and objective measures. GABAA benzodiazepine receptor sensitivity was significantly reduced in the patient group. Conclusions: Chronic treatment with benzodiazepines was associated with reduced effects of midazolam. Saccadic eye movement velocity was especially sensitive as a measure of attenuated response.

Key words Benzodiazepine GABAA receptor Tolerance Saccadic eye movement 

Copyright information

© Springer-Verlag Berlin Heidelberg 1999

Authors and Affiliations

  • J. Potokar
    • 1
  • Nick Coupland
    • 2
  • S. Wilson
    • 1
  • A. Rich
    • 1
  • David Nutt
    • 1
  1. 1.Psychopharmacology Unit, University of Bristol, School of Medical Sciences, University Walk, Bristol BS8 2BA, UK Fax: +44-117-9277057GB
  2. 2.Department of Psychiatry, University of Alberta, 1E7.28 MacKenzie Centre, 8440-112 Street, Edmonton, Alberta, Canada T6G 2B7CA

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