Journal Article

Concentration-Time Profiles of Gamma-Hydroxybutyrate in Blood After Recreational Doses are Best Described by Zero-Order Rather Than First-Order Kinetics

A.W. Jones, A. Eklund and R. Kronstrand

in Journal of Analytical Toxicology

Volume 33, issue 6, pages 332-335
Published in print July 2009 | ISSN: 0146-4760
Published online July 2009 | e-ISSN: 1945-2403 | DOI: http://dx.doi.org/10.1093/jat/33.6.332
Concentration-Time Profiles of Gamma-Hydroxybutyrate in Blood After Recreational Doses are Best Described by Zero-Order Rather Than First-Order Kinetics

More Like This

Show all results sharing these subjects:

  • Medical Toxicology
  • Toxicology (Non-medical)

GO

Show Summary Details

Preview

The recreational drug gamma-hydroxybutyrate (GHB) has a short plasma elimination half-life (t½) reported to be about 30–50 min. However, this represents a terminal half-life and therefore might not necessarily apply after large (abuse) doses are taken. Clinical studies with sodium oxybate (sodium salt of GHB) suggest that zero-order rather than first-order kinetics are more appropriate to describe post-peak concentration-time (C-T) profiles. We report the case of a 23-year-old male found unconscious by the police and a blood sample contained 100 mg/L GHB and 0.14 g% ethanol. On regaining consciousness the man admitted drinking alcohol about 6 h earlier but claimed that his drink must have been spiked with GHB. The police wanted to know how much GHB had been administered to account for the man's clinical condition. A back-calculation for 6 h, assuming a GHB half-life of 40 min, gives a very high concentration in blood of ∼900 mg/L, which would probably have proven fatal. Back-calculating using zero-order kinetics and a proposed elimination rate of 18 mg/L per hour leads to a GHB concentration of 208 mg/L, which is much more realistic. Toxicologists should not arbitrarily apply the principles of first-order kinetics after abuse doses of drugs, when zero-order or saturation kinetics (Michaelis-Menten) are more appropriate.

Journal Article.  0 words. 

Subjects: Medical Toxicology ; Toxicology (Non-medical)

Full text: subscription required

How to subscribe Recommend to my Librarian

Users without a subscription are not able to see the full content. Please, subscribe or login to access all content.