Interindividual variation in the pharmacokinetics of Delta9-tetrahydrocannabinol as related to genetic polymorphisms in CYP2C9

Clin Pharmacol Ther. 2009 Mar;85(3):273-6. doi: 10.1038/clpt.2008.213. Epub 2008 Nov 12.


The impact of the CYP2C9 polymorphism on the pharmacokinetics of orally administered 9-tetrahydrocannabinol (THC) was studied in 43 healthy volunteers. THC pharmacokinetics did not differ by CYP2C9*2 allele status. However, the median area under the curve of THC was threefold higher and that of 11-nor-9-carboxy-9-tetrahydrocannabinol was 70% lower in CYP2C9*3/*3 homozygotes than in CYP2C9*1/*1 homozygotes. CYP2C9*3 carriers also showed a trend toward increased sedation following administration of THC. Therefore, the CYP2C9*3 variant may influence both the therapeutic and adverse effects of THC.

Publication types

  • Comparative Study

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Alleles*
  • Aryl Hydrocarbon Hydroxylases / genetics*
  • Aryl Hydrocarbon Hydroxylases / metabolism
  • Cytochrome P-450 CYP2C9
  • Dronabinol / blood
  • Dronabinol / pharmacokinetics*
  • Female
  • Gene Frequency / genetics
  • Genetic Variation / genetics*
  • Humans
  • Male
  • Middle Aged
  • Polymorphism, Genetic / genetics*
  • Sex Factors
  • Young Adult


  • Dronabinol
  • CYP2C9 protein, human
  • Cytochrome P-450 CYP2C9
  • Aryl Hydrocarbon Hydroxylases