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Psychopharmacology (Berl). 2008 Dec;201(2):171-81. doi: 10.1007/s00213-008-1260-2. Epub 2008 Aug 10.

Delta-9-tetrahydrocannabinol (THC) serum concentrations and pharmacological effects in males after smoking a combination of tobacco and cannabis containing up to 69 mg THC.

Author information

1
National Institute for Public Health and the Environment, P.O. Box 1, 3720 BA, Bilthoven, The Netherlands. claudine.hunault@rivm.nl

Abstract

RATIONALE:

Delta9-Tetrahydrocannabinol (THC) is the main active constituent of cannabis. In recent years, the average THC content of some cannabis cigarettes has increased up to approximately 60 mg per cigarette (20% THC cigarettes). The pharmacokinetics of THC after smoking cannabis cigarettes containing more than approximately 35 mg THC (3.55% THC cigarettes) is unknown. To be able to perform suitable exposure risk analysis, it is important to know if there is a linear relation at higher doses.

OBJECTIVES:

The present study aimed to characterise the pharmacokinetics of THC, the active metabolite 11-OH-THC and the inactive metabolite THC-COOH after smoking a combination of tobacco and cannabis containing high THC doses.

MATERIALS AND METHODS:

This double-blind, placebo-controlled, four-way, cross-over study included 24 male non-daily cannabis users (two to nine joints per month). Participants were randomly assigned to smoke cannabis cigarettes containing 29.3, 49.1 and 69.4 mg THC and a placebo. Serial serum samples collected over a period of 0-8 h were analysed by liquid chromatography electrospray tandem mass spectrometry. Effects on heart rate, blood pressure and 'high' feeling were also measured.

RESULTS:

Mean maximal concentrations (Cmax) were 135.1, 202.9 and 231.0 microg/L for THC and 9.2, 16.4 and 15.8 microg/L for 11-OH-THC after smoking a 29.3-, 49.1- and 69.4-mg THC cigarette, respectively. A large inter-individual variability in Cmax was observed. Heart rate and 'high' feeling significantly increased with increasing THC dose.

CONCLUSIONS:

This study demonstrates that the known linear association between THC dose and THC serum concentration also applies for high THC doses.

PMID:
18695931
DOI:
10.1007/s00213-008-1260-2
[Indexed for MEDLINE]

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