Can oral fluid cannabinoid testing monitor medication compliance and/or cannabis smoking during oral THC and oromucosal Sativex administration?

OBJECTIVES: We characterize cannabinoid disposition in oral fluid (OF) after dronabinol, synthetic oral Δ(9)-tetrahydrocannabinol (THC), and Sativex, a cannabis-extract oromucosal spray, and evaluate whether smoked cannabis relapse or Sativex compliance can be identified with OF cannabinoid monitoring. METHODS: 5 and 15 mg synthetic oral THC, low (5.4 mg THC, 5.0 mg cannabidiol (CBD)) and high (16.2 mg THC, 15.0 mg CBD) dose Sativex, and placebo were administered in random order (n=14). Oral fluid specimens were collected for 10.5 h after dosing and analyzed for THC, CBD, cannabinol (CBN), and 11-nor-9-carboxy-THC (THCCOOH). RESULTS: After oral THC, OF THC concentrations decreased over time from baseline, reflecting residual THC excretion from previously self-administered smoked cannabis. CBD and CBN also were rarely detected. After Sativex, THC, CBD and CBN increased greatly, peaking at 0.25-1 h. Median CBD/THC and CBN/THC ratios were 0.82-1.34 and 0.04-0.06, respectively, reflecting cannabinoids' composition in Sativex. THCCOOH/THC ratios within 4.5 h post Sativex were ≤ 1.6 pg/ng, always lower than after oral THC and placebo. THCCOOH/THC ratios increased throughout each dosing session. CONCLUSIONS: Lack of measurable THC, CBD and CBN in OF following oral THC, and high OF CBD/THC ratios after Sativex distinguish oral and sublingual drug delivery routes from cannabis smoking. Low THCCOOH/THC ratios suggest recent Sativex and smoked cannabis exposure. These data indicate that OF cannabinoid monitoring can document compliance with Sativex pharmacotherapy, and identify relapse to smoked cannabis during oral THC medication but not Sativex treatment, unless samples were collected shortly after smoking.

Plasma cannabinoid pharmacokinetics following controlled oral delta9-tetrahydrocannabinol and oromucosal cannabis extract administration.

BACKGROUND: Sativex(®), a cannabis extract oromucosal spray containing Δ(9)-tetrahydrocannabinol (THC) and cannabidiol (CBD), is currently in phase III trials as an adjunct to opioids for cancer pain treatment, and recently received United Kingdom approval for treatment of spasticity. There are indications that CBD modulates THC's effects, but it is unclear if this is due to a pharmacokinetic and/or pharmacodynamic interaction. METHODS: Cannabis smokers provided written informed consent to participate in this randomized, controlled, double-blind, double-dummy institutional review board-approved study. Participants received 5 and 15 mg synthetic oral THC, low-dose (5.4 mg THC and 5.0 mg CBD) and high-dose (16.2 mg THC and 15.0 mg CBD) Sativex, and placebo over 5 sessions. CBD, THC, 11-hydroxy-THC, and 11-nor- 9-carboxy-THC were quantified in plasma by 2-dimensional GC-MS. Lower limits of quantification were ≤0.25 µg/L. RESULTS: Nine cannabis smokers completed all 5 dosing sessions. Significant differences (P < 0.05) in maximum plasma concentrations (C(max)) and areas under the curve from 0-10.5 h postdose (AUC(0→10.5)) for all analytes were found between low and high doses of synthetic THC and Sativex. There were no statistically significant differences in C(max), time to maximum concentration or in the AUC(0→10.5) between similar oral THC and Sativex doses. Relative bioavailability was calculated to determine the relative rate and extent of THC absorption; 5 and 15 mg oral THC bioavailability was 92.6% (13.1%) and 98.8% (11.0%) of low- and high-dose Sativex, respectively. CONCLUSION: These data suggest that CBD modulation of THC's effects is not due to a pharmacokinetic interaction at these therapeutic doses.