Randomized pharmacodynamic and pharmacogenetic trial of dronabinol effects on colon transit in irritable bowel syndrome-diarrhea

B. S. Wong, M. Camilleri, D. Eckert, P. Carlson, M. Ryks, D. Burton, A. R. Zinsmeister

Research output: Contribution to journalArticle

43 Scopus citations

Abstract

Background Genetic variation in endocannabinoid metabolism is associated with colonic transit in irritable bowel syndrome (IBS) with diarrhea (IBS-D). The nonselective cannabinoid (CB) receptor agonist, dronabinol (DRO), reduced fasting colonic motility in nonconstipated IBS. FAAH and CNR1 variants influenced DRO's effects on colonic motility. Our aims were: (i) to compare dose-related effects of DRO to placebo (PLA) on gut transit in IBS-D, and (ii) to examine influence of genetic variations in CB mechanisms on DRO's transit effects. Methods Thirty-six IBS-D volunteers were randomized (double-blind, concealed allocation) to twice per day PLA (n=13), DRO 2.5mg (n=10), or DRO 5mg (n=13) for 2days. We assessed gastric, small bowel, and colonic transit by validated radioscintigraphy and genotyped the single nucleotide polymorphisms CNR1 rs806378 and FAAH rs324420. Data analysis utilized a dominant genetic model. Key Results Overall treatment effects of DRO on gastric, small bowel, or colonic transit were not detected. CNR1 rs806378 CT/TT was associated with a modest delay in colonic transit at 24h compared with CC (P=0.13 for differential treatment effects on postminus pretreatment changes in colonic transit by genotype). No significant interaction of treatment with FAAH rs324420 was detected. Conclusions & Inferences Overall, DRO 2.5 or 5mg twice per day for 2days had no effect on gut transit in IBS-D. There appears to be a treatment-by-genotype effect, whereby DRO preferentially delays colonic transit in those with the CNR1 rs806378 CT/TT genotypes. Further study of CB pharmacogenetics may help identify a subset of IBS-D patients most likely to benefit from CB agonist therapy.

Original languageEnglish (US)
Pages (from-to)358-e169
JournalNeurogastroenterology and Motility
Volume24
Issue number4
DOIs
StatePublished - Apr 1 2012

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Keywords

  • Anandamide
  • Cannabinoid
  • Fatty acid amide hydrolase
  • Gastric
  • Motility
  • Nonselective
  • Receptor
  • Small bowel

ASJC Scopus subject areas

  • Physiology
  • Endocrine and Autonomic Systems
  • Gastroenterology

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