title: Influence of ethanol on the pharmacokinetic properties of Δ9-tetrahydrocannabinol in oral fluid.
abstract: Oral fluid (OF) tests aid in identifying drivers under the influence of drugs. In this study, 17 heavy cannabis users consumed alcohol to achieve steady blood alcohol concentrations of 0 to 0.7 g/L and smoked cannabis 3 h afterward. OF samples were obtained before and up to 4 h after smoking and on-site tests were performed (Dräger DrugTest 5000 and Securetec DrugWipe 5+). Maximum concentrations of tetrahydrocannabinol (THC) immediately after smoking (up to 44,412 ng/g) were below 4,300 (median 377) ng/g 1 h after smoking and less than 312 (median 88) ng/g 3 h later with 5 of 49 samples negative, suggesting that recent cannabis use might occasionally not be detectable. An influence of alcohol was not observed. Drinking 300 mL variably influenced THC concentrations (median only -29.6%), which suggests that drinking does not markedly affect on-site test performance. Many (92%) Dräger tests performed 4 h after smoking were still positive, indicating sufficient sensitivity for recent cannabis use. Differences in the results of a roadside study with DrugTest 5000 (sensitivity 84.8%, specificity 96.0%, accuracy 84.3%) could be explained by a higher number of true negatives, differences between OF and serum and differences between occasional and chronic users.
authors: Institute of Legal Medicine, University of Frankfurt/Main, Germany. toennes@em.uni-frankfurt.de
authors: Stefan W
authors: SW
authors: Toennes
authors: Kirsten
authors: K
authors: Schneider
authors: Cora
authors: C
authors: Wunder
authors: Gerold F
authors: GF
authors: Kauert
authors: Manfred R
authors: MR
authors: Moeller
authors: Eef L
authors: EL
authors: Theunissen
authors: Johannes G
authors: JG
authors: Ramaekers
mesh_terms: D000328:Adult; D000428:Alcohol Drinking / Q000097:blood / Q000378:metabolism*; D000434:Alcoholic Beverages; D001334:Automobile Driving; D003415:Crime; D018592:Cross-Over Studies; D004311:Double-Blind Method; D013759:Dronabinol / Q000097:blood / Q000493:pharmacokinetics*; D004347:Drug Interactions; D000431:Ethanol / Q000008:administration & dosage* / Q000097:blood; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D008297:Male; D002189:Marijuana Abuse / Q000097:blood / Q000378:metabolism*; D008385:Marijuana Smoking / Q000097:blood / Q000378:metabolism*; D009426:Netherlands; D011237:Predictive Value of Tests; D012463:Saliva / Q000378:metabolism*; D012680:Sensitivity and Specificity; D015813:Substance Abuse Detection / Q000379:methods; D055815:Young Adult
chemical_list: D000431:Ethanol; D013759:Dronabinol