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. 2013 Mar;59(3):519-26.
doi: 10.1373/clinchem.2012.195503.

Impact of prolonged cannabinoid excretion in chronic daily cannabis smokers' blood on per se drugged driving laws

Mateus M Bergamaschi  1 , Erin L Karschner, Robert S Goodwin, Karl B Scheidweiler, Jussi Hirvonen, Regina H C Queiroz, Marilyn A Huestis
Affiliations

Impact of prolonged cannabinoid excretion in chronic daily cannabis smokers' blood on per se drugged driving laws

Mateus M Bergamaschi et al. Clin Chem. 2013 Mar.

Abstract

Background: Cannabis is the illicit drug most frequently reported with impaired driving and motor vehicle accidents. Some "per se" laws make it illegal to drive with any amount of drug in the body, while others establish blood, saliva, or urine concentrations above which it is illegal to drive. The persistence of Δ(9)-tetrahydrocannabinol (THC) in chronic daily cannabis smokers' blood is unknown.

Methods: Thirty male chronic daily cannabis smokers resided on a secure research unit for up to 33 days, with daily blood collection. Samples were processed in an ice bath during sample preparation to minimize cannabinoid adsorption onto precipitant material. We quantified THC by 2-dimensional GC-MS.

Results: Of the 30 participants, 27 were THC-positive on admission, with a median (range) concentration of 1.4 μg/L (0.3-6.3). THC decreased gradually; only 1 of 11 participants was negative at 26 days, 2 of 5 remained THC-positive (0.3 μg/L) for 30 days, and 5.0% of participants had THC ≥ 1.0 μg/L for 12 days. Median 11-hydroxy-THC concentrations were 1.1 μg/L on admission, with no results ≥ 1.0 μg/L 24 h later. 11-Nor-9-carboxy-THC (THCCOOH) detection rates were 96.7% on admission, decreasing slowly to 95.7% and 85.7% on days 8 and 22, respectively; 4 of 5 participants remained THCCOOH positive (0.6-2.7 μg/L) after 30 days, and 1 remained positive on discharge at 33 days.

Conclusions: Cannabinoids can be detected in blood of chronic daily cannabis smokers during a month of sustained abstinence. This is consistent with the time course of persisting neurocognitive impairment reported in recent studies.

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Conflict of interest statement

Authors’ Disclosures or Potential Conflicts of Interest: Upon manuscript submission, all authors completed the author disclosure form. Disclosures and/or potential conflicts of interest:

Employment or Leadership: None declared.

Consultant or Advisory Role: None declared.

Stock Ownership: None declared.

Honoraria: None declared.

Research Funding: M.M. Bergamaschi, CAPES (Brazilian Federal Agency for the Support and Evaluation of Graduate Education); M.A. Huestis, Intramural Research Program, National Institute on Drug Abuse and National Institute of Mental Health, NIH.

Expert Testimony: None declared.

Figures

Fig. 1
Fig. 1
Cannabinoid detection rates in chronic daily cannabis smokers on the basis of the method’s limits of quantification, 0.25 μg/L for THC and THCCOOH and 0.5 μg/L for 11-OH-THC.
Fig. 2
Fig. 2. Kaplan–Meier plot for detection of THC and 11-OH-THC in blood during 33 days of sustained abstinence in chronic daily cannabis smokers
THCCOOH was not included because it was positive in most individual’s blood samples until the time of discharge. Censored data represented by the small vertical ticks on the plotted lines are study participants who left the study before achieving negative THC or negative 11-OH-THC results on 4 or 2 consecutive days, respectively.
See this image and copyright information in PMC

References

    1. United Nations Office on Drugs and Crime (UNODC) World Drug Report 2011. New York: 2011. p. 272.
    1. Substance Abuse and Mental Health Services Administration (SAMHSA) Results from the 2010 National Survey on Drug Use and Health: summary of national findings. Rockville (MD): SAMHSA; 2011. NSDUH Series H-41, HHS publ. no. (SMA) 11-4658.
    1. Elkashef A, Vocci F, Huestis M, Haney M, Budney A, Gruber A, el-Guebaly N. Marijuana neurobiology and treatment. Subst Abus. 2008;29:17–29. - PMC - PubMed
    1. Ramaekers J, Kauert G, Theunissen E, Toennes S, Moeller M. Neurocognitive performance during acute THC intoxication in heavy and occasional cannabis users. J Psychopharmacol. 2009;23:266–77. - PubMed
    1. Lane SD, Cherek DR, Tcheremissine OV, Lieving LM, Pietras CJ. Acute marijuana effects on human risk taking. Neuropsychopharmacology. 2005;30:800–9. - PubMed

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