Cannabis constituents interact at the drug efflux pump BCRP to markedly increase plasma cannabidiolic acid concentrations.

Cannabis is a complex mixture of hundreds of bioactive molecules. This provides the potential for pharmacological interactions between cannabis constituents, a phenomenon referred to as "the entourage effect" by the medicinal cannabis community. We hypothesize that pharmacokinetic interactions between cannabis constituents could substantially alter systemic cannabinoid concentrations. To address this hypothesis we compared pharmacokinetic parameters of cannabinoids administered orally in a cannabis extract to those administered as individual cannabinoids at equivalent doses in mice. Astonishingly, plasma cannabidiolic acid (CBDA) concentrations were 14-times higher following administration in the cannabis extract than when administered as a single molecule. In vitro transwell assays identified CBDA as a substrate of the drug efflux transporter breast cancer resistance protein (BCRP), and that cannabigerol and Δ9-tetrahydrocannabinol inhibited the BCRP-mediated transport of CBDA. Such a cannabinoid-cannabinoid interaction at BCRP transporters located in the intestine would inhibit efflux of CBDA, thus resulting in increased plasma concentrations. Our results suggest that cannabis extracts provide a natural vehicle to substantially enhance plasma CBDA concentrations. Moreover, CBDA might have a more significant contribution to the pharmacological effects of orally administered cannabis extracts than previously thought.

Intoxication by a synthetic cannabinoid (JWH-018) causes cognitive and psychomotor impairment in recreational cannabis users.

BACKGROUND: Smoking mixtures containing synthetic cannabinoids (SCs) have become very popular over the last years but pose a serious risk for public health. Limited knowledge is, however, available regarding the acute effects of SCs on cognition and psychomotor performance. Earlier we demonstrated signs of impairment in healthy volunteers after administering one of the first SCs, JWH-018, even though subjective intoxication was low. In the current study, we aimed to investigate the acute effects of JWH-018 on several cognitive and psychomotor tasks in participants who are demonstrating representative levels of acute intoxication. METHODS: 24 healthy cannabis-experienced participants took part in this placebo-controlled, cross-over study. Participants inhaled the vapor of 75 µg JWH-018/kg body weight and were given a booster dose if needed to induce a minimum level of subjective high. They were subsequently monitored for 4 h, during which psychomotor and cognitive performance, vital signs, and subjective experience were measured, and serum concentrations were determined. RESULTS: Maximum subjective high (average 64%) was reached 30 min after administration of JWH-018, while the maximum blood concentration was shown after 5 min (8 ng/mL). JWH-018 impaired motor coordination (CTT), attention (DAT and SST), memory (SMT), it lowered speed-accuracy efficiency (MFFT) and slowed down response speed (DAT). CONCLUSION: In accordance with our previous studies, we demonstrated acute psychomotor and cognitive effects of a relatively low dose of JWH-018.

Differential physiological and behavioral cues observed in individuals smoking botanical marijuana versus synthetic cannabinoid drugs.

CONTEXT: Synthetic cannabinoid use has increased in many states, and medicinal and/or recreational marijuana use has been legalized in some states. These changes present challenges to law enforcement drug recognition experts (DREs) who determine whether drivers are impaired by synthetic cannabinoids or marijuana, as well as to clinical toxicologists who care for patients with complications from synthetic cannabinoids and marijuana. Our goal was to compare what effects synthetic cannabinoids and marijuana had on performance and behavior, including driving impairment, by reviewing records generated by law enforcement DREs who evaluated motorists arrested for impaired driving. METHODS: Data were from a retrospective, convenience sample of de-identified arrest reports from impaired drivers suspected of using synthetic cannabinoids (n = 100) or marijuana (n = 33). Inclusion criteria were arrested drivers who admitted to using either synthetic cannabinoids or marijuana, or who possessed either synthetic cannabinoids or marijuana; who also had a DRE evaluation at the scene; and whose blood screens were negative for alcohol and other drugs. Exclusion criteria were impaired drivers arrested with other intoxicants found in their drug or alcohol blood screens. Blood samples were analyzed for 20 popular synthetic cannabinoids by using liquid chromatography-tandem mass spectrometry. Delta-9-tetrahydrocannabinol (THC) and THC-COOH were quantified by gas chromatography-mass spectrometry. Statistical significance was determined by using Fisher's exact test or Student's t-test, where appropriate, to compare the frequency of characteristics of those in the synthetic cannabinoid group versus those in the marijuana group. RESULTS: 16 synthetic cannabinoid and 25 marijuana records met selection criteria; the drivers of these records were arrested for moving violations. Median age for the synthetic cannabinoid group (n = 16, 15 males) was 20 years (IQR 19-23 years). Median age for the marijuana group (n = 25, 21 males) was 20 years (IQR 19-24 years) (p = 0.46). In the synthetic cannabinoid group, 94% (15/16) admitted to using synthetic cannabinoids. In the marijuana group, 96% (24/25) admitted to using marijuana. Blood was available for testing in 96% (24/25) of the marijuana group; 21 of these 24 had quantitative levels of THC (mean + SD = 10.7 + 5 ng/mL) and THC-COOH (mean + SD = 57.8 + 3 ng/mL). Blood was available for testing in 63% (10/16) of the synthetic cannabinoid group, with 80% (8/10) of these positive for synthetic cannabinoids. Those in the synthetic cannabinoid group were more frequently confused (7/16 [44%] vs. 0/25 [0%], p ≤ 0.003) and disoriented (5/16 [31%] vs. 0/25 [0%], p ≤ 0.003), and more frequently had incoherent, slurred speech (10/16 [63%] vs. 3/25 [12%], p = 0.0014) and horizontal gaze nystagmus (8/16 [50%] vs. 3/25 [12%], p = 0.01) than those in the marijuana group. CONCLUSION: Drivers under the influence of synthetic cannabinoids were more frequently impaired with confusion, disorientation, and incoherent, slurred speech than drivers under the influence of marijuana in this population evaluated by DREs.

Buspirone treatment of cannabis dependence: A randomized, placebo-controlled trial.

BACKGROUND: The purpose of this study was to evaluate the efficacy of buspirone, a partial 5-HT1A agonist, for treatment of cannabis dependence. METHODS: One hundred seventy-five cannabis-dependent adults were randomized to receive either up to 60mg/day of buspirone (n=88) or placebo (n=87) for 12 weeks combined with a brief motivational enhancement therapy intervention and contingency management to encourage study retention. Cannabis use outcomes were assessed via weekly urine cannabinoid tests. RESULTS: Participants in both groups reported reduced cannabis craving over the course of the study; however, buspirone provided no advantage over placebo in reducing cannabis use. Significant gender by treatment interactions were observed, with women randomized to buspirone having fewer negative urine cannabinoid tests than women randomized to placebo (p=0.007), and men randomized to buspirone having significantly lower creatinine adjusted cannabinoid levels as compared to those randomized to placebo (p=0.023). An evaluation of serotonin allelic variations did not find an association with buspirone treatment response. CONCLUSIONS: Buspirone was not more efficacious than placebo in reducing cannabis use. Important gender differences were noted, with women having worse cannabis use outcomes with buspirone treatment. Considerations for future medication trials in this challenging population are discussed.

Rivastigmine but not vardenafil reverses cannabis-induced impairment of verbal memory in healthy humans.

RATIONALE: One of the most often reported cognitive deficits of acute cannabis administration is an impaired recall of previously learned information. OBJECTIVE: The aim of the present study was to determine whether cannabis-induced memory impairment in humans is mediated via glutamatergic or cholinergic pathways. METHODS: Fifteen occasional cannabis users participated in a double-blind, placebo-controlled, six-way cross-over study. On separate test days, subjects received combinations of pretreatment (placebo, vardenafil 20 mg or rivastigmine 3 mg) and treatment (placebo or 1,376 mg cannabis/kg body weight). Cognitive tests were administered immediately after inhalation of treatment was finished and included measures of memory (visual verbal learning task, prospective memory test, Sternberg memory test), perceptual-motor control (critical tracking task), attention (divided attention task) and motor impulsivity (stop signal task). RESULTS: The results of this study demonstrate that subjects under the influence of cannabis were impaired in all memory tasks, in critical tracking, divided attention and the stop signal task. Pretreatment with rivastigmine attenuated the effect of cannabis on delayed recall and showed a trend towards significance on immediate recall. When cannabis was given in combination with vardenafil, there were no significant interaction effects in any of the tasks. CONCLUSIONS: The present data therefore suggest that acetylcholine plays an important role in cannabis-induced memory impairment, whereas similar results for glutamate have not been demonstrated in this study.

Lithium carbonate in the management of cannabis withdrawal: a randomized placebo-controlled trial in an inpatient setting.

RATIONALE: Preclinical studies suggest that lithium carbonate (lithium) can reduce precipitated cannabinoid withdrawal in rats by stimulating release of the neuropeptide oxytocin, while two open-label studies indicate lithium may ameliorate cannabis withdrawal symptoms in humans. OBJECTIVES: This study was conducted to examine the efficacy and safety of lithium in the inpatient management of cannabis withdrawal and to determine whether lithium affects plasma oxytocin and the rate of elimination of plasma cannabinoids during abstinence. METHODS: Treatment-seeking cannabis-dependent adults (n = 38) were admitted for 8 days to an inpatient withdrawal unit and randomized to either oral lithium (500 mg) or placebo given twice a day under double-blind randomized controlled trial (RCT) conditions. Primary outcomes included withdrawal severity [cannabis withdrawal scale (CWS)], rates of detoxification completion, and adverse events. Plasma cannabinoids, plasma oxytocin and serum lithium levels were measured repeatedly over admission. Follow-up research interviews were conducted at 14, 30, and 90 days postdischarge. RESULTS: Lithium did not significantly affect total CWS scores relative to placebo, although it significantly reduced individual symptoms of "loss of appetite," "stomach aches," and "nightmares/strange dreams." No significant group differences were found in treatment retention or adverse events. Lithium did not increase plasma oxytocin levels nor influence the rate of elimination of cannabinoids. Both placebo- and lithium-treated participants showed reduced levels of cannabis use (verified by urinalysis) and improved health and psychosocial outcomes at 30- and 90-day follow-up relative to pretreatment baselines. CONCLUSIONS: Despite the strong rationale for the present study, the efficacy of lithium over placebo in the management of cannabis withdrawal was not demonstrated.

Plasma cannabinoid concentrations during dronabinol pharmacotherapy for cannabis dependence.

BACKGROUND: Recently, high-dose oral synthetic delta-9-tetrahydrocannabinol (THC) was shown to alleviate cannabis withdrawal symptoms. The present data describe cannabinoid pharmacokinetics in chronic, daily cannabis smokers who received high-dose oral THC pharmacotherapy and later a smoked cannabis challenge. METHODS: Eleven daily cannabis smokers received 0, 30, 60, or 120 mg/d THC for four 5-day medication sessions, each separated by 9 days of ad libitum cannabis smoking. On the fifth day, participants were challenged with smoking one 5.9% THC cigarette. Plasma collected on the first and fifth days was quantified by two-dimensional gas chromatography mass spectrometer for THC, 11-hydroxy-THC (11-OH-THC), and 11-nor-9-carboxy-THC (THCCOOH). Linear ranges (ng/mL) were 0.5-100 for THC, 1-50 for 11-OH-THC, and 0.5-200 for THCCOOH. RESULTS: During placebo dosing, THC, 11-OH-THC, and THCCOOH concentrations consistently decreased, whereas all cannabinoids increased dose dependently during active dronabinol administration. THC increase over time was not significant after any dose, 11-OH-THC increased significantly during the 60- and 120-mg/d doses, and THCCOOH increased significantly only during the 120-mg/d dose. THC, 11-OH-THC, and THCCOOH concentrations peaked within 0.25 hours after cannabis smoking, except after 120 mg/d THC when THCCOOH peaked 0.5 hours before smoking. CONCLUSIONS: The significant withdrawal effects noted during placebo dronabinol administration were supported by significant plasma THC and 11-OH-THC concentration decreases. During active dronabinol dosing, significant dose-dependent increases in THC and 11-OH-THC concentrations support withdrawal symptom suppression. THC concentrations after cannabis smoking were only distinguishable from oral THC doses for 1 hour, too short a period to feasibly identify cannabis relapse. THCCOOH/THC ratios were higher 14 hours after overnight oral dronabinol abstinence but cannot distinguish oral THC dosing from the smoked cannabis intake.

Acute toxicity due to the confirmed consumption of synthetic cannabinoids: clinical and laboratory findings.

AIMS: Recently, several synthetic cannabinoids were identified in herbal mixtures consumed as recreational drugs alternative to cannabis products. The aim was to characterize the acute toxicity of synthetic cannabinoids as experienced by emergency patients. DESIGN: This was a retrospective study targeting patients seeking emergency treatment after recreational use of synthetic cannabinoids. SETTING AND PARTICIPANTS: Patients were selected from the database of the Poisons Information Center Freiburg between September 2008 and February 2011. The inclusion criteria were: hospitalization, available clinical reports and analytical verification of synthetic cannabinoid uptake. In total, 29 patients were included (age 14-30 years, median 19; 25 males, four females). MEASUREMENTS: Clinical reports were evaluated and synthetic cannabinoids and other drugs were determined analytically. FINDINGS: CP-47,497-C8 (one), JWH-015 (one), JWH-018 (eight), JWH-073 (one), JWH-081 (seven), JWH-122 (11), JWH-210 (11), JWH-250 (four) and AM 694 (one) were quantified in blood samples. JWH-018 was most common in 2008-9, JWH-122 in 2010, and JWH-210 in 2011. Tachycardia, agitation, hallucination, hypertension, minor elevation of blood glucose, hypokalaemia and vomiting were reported most frequently. Chest pain, seizures, myoclonia and acute psychosis were also noted. CONCLUSIONS: There appears to have been an increase in use of the extremely potent synthetic cannabinoids JWH-122 and JWH-210. Acute toxic symptoms associated with their use are also reported after intake of high doses of cannabis, but agitation, seizures, hypertension, emesis and hypokalaemia seem to be characteristic to the synthetic cannabinoids, which are high-affinity and high-efficacy agonists of the CB(1) receptor. Thus, these effects are due probably to a strong CB(1) receptor stimulation.

A randomized, double-blind, placebo-controlled, crossover study to evaluate the subjective abuse potential and cognitive effects of nabiximols oromucosal spray in subjects with a history of recreational cannabis use.

OBJECTIVE: This study aimed to evaluate the abuse potential and cognitive effects of nabiximols (Sativex, GW Pharma Ltd. Salisbury, UK), an oromucosal spray primarily containing delta­9­tetrahydrocannabinol (THC) and cannabidiol (CBD). METHODS: This was a single­dose, randomized, double­blind, crossover study comparing nabiximols (4, 8, and 16 consecutive sprays: 10.8, 21.6, and 43.2 mg THC, respectively) with dronabinol 20 and 40 mg (synthetic THC: Marinol, Solvay Pharmaceuticals, Brussels, Belgium) and matching placebos in 23 recreational cannabis users. Subjective and cognitive/psychomotor measures were administered over 24 h post­dose. RESULTS: Dronabinol was significantly different from placebo on abuse potential measures, thereby confirming study validity. Nabiximols 10.8 mg was not significantly different from placebo on primary measures but was different on some secondary measures. Nabiximols 21.6 mg was significantly greater than placebo on some primary/secondary measures, whereas nabiximols 43.2 mg showed significant effects on most measures. Nabiximols 10.8 mg was significantly lower than dronabinol doses on most measures ( p < 0.05). Dronabinol 20 mg effects were numerically higher than nabiximols 21.6 mg but were statistically significant only for some measures. Dronabinol 40 mg and nabiximols 43.2 mg were generally not statistically different. CONCLUSIONS: Both dronabinol and nabiximols had significant abuse potential compared with placebo at higher doses. Nabiximols showed similar or slightly less abuse potential compared with dronabinol. Therefore, the abuse potential of nabiximols should be no higher than that of dronabinol.

Dose-dependent effects of smoked cannabis on capsaicin-induced pain and hyperalgesia in healthy volunteers.

BACKGROUND: Although the preclinical literature suggests that cannabinoids produce antinociception and antihyperalgesic effects, efficacy in the human pain state remains unclear. Using a human experimental pain model, the authors hypothesized that inhaled cannabis would reduce the pain and hyperalgesia induced by intradermal capsaicin. METHODS: In a randomized, double-blinded, placebo-controlled, crossover trial in 15 healthy volunteers, the authors evaluated concentration-response effects of low-, medium-, and high-dose smoked cannabis (respectively 2%, 4%, and 8% 9-delta-tetrahydrocannabinol by weight) on pain and cutaneous hyperalgesia induced by intradermal capsaicin. Capsaicin was injected into opposite forearms 5 and 45 min after drug exposure, and pain, hyperalgesia, tetrahydrocannabinol plasma levels, and side effects were assessed. RESULTS: Five minutes after cannabis exposure, there was no effect on capsaicin-induced pain at any dose. By 45 min after cannabis exposure, however, there was a significant decrease in capsaicin-induced pain with the medium dose and a significant increase in capsaicin-induced pain with the high dose. There was no effect seen with the low dose, nor was there an effect on the area of hyperalgesia at any dose. Significant negative correlations between pain perception and plasma delta-9-tetrahydrocannabinol levels were found after adjusting for the overall dose effects. There was no significant difference in performance on the neuropsychological tests. CONCLUSIONS: This study suggests that there is a window of modest analgesia for smoked cannabis, with lower doses decreasing pain and higher doses increasing pain.

Development of a LC/MS/MS method for the analysis of cannabinoids in human EDTA-plasma and urine after small doses of Cannabis sativa extracts.

A novel high-performance liquid chromatographic separation method with tandem-mass spectrometry detection was developed for the simultaneous determination of Delta(9)-tetrahydrocannabinol (THC) and its major metabolites 11-hydroxy-Delta(9)-tetrahydrocannabinol (11-OH-THC) and 11-nor-Delta(9)-tetrahydrocannabinol-9-carboxylic acid (THC-COOH) as well as the components cannabidiol (CBD) and cannabinol (CBN) in human EDTA-plasma and urine. Run time was 25 min. Lower limit of quantification was 0.2 ng/ml. The coefficients of variation of all inter- and intra-assay determinations were between 1.3 and 15.5%. The method was successfully applied to the determination of cannabinoids in human plasma and human urine after administration of Delta(9)-tetrahydrocannabinol or Cannabis sativa extracts.

Delta(9)-tetrahydrocannabinol, 11-hydroxy-delta(9)-tetrahydrocannabinol and 11-nor-9-carboxy-delta(9)-tetrahydrocannabinol in human plasma after controlled oral administration of cannabinoids.

A clinical study to investigate the pharmacokinetics and pharmacodynamics of oral tetrahydrocannabinol was performed. This randomized, double-blind, placebo-controlled, within-subject, inpatient study compared the effects of THC-containing hemp oils in liquid and capsule form to dronabinol (synthetic THC) in doses used for appetite stimulation. The National Institute on Drug Abuse Institutional Review Board approved the protocol and each participant provided informed consent. Detection times and concentrations of THC, 11-hydroxy-Delta-tetrahydrocannabinol (11-OH-THC), and 11-nor-9-carboxy-Delta-tetrahydrocannabinol (THCCOOH) in plasma were determined by gas chromatography-mass spectrometry [limits of quantification (LOQ)=0.5, 0.5, and 1.0 ng/mL, respectively] after oral THC administration. Six volunteers ingested liquid hemp oil (0.39 and 14.8 mg THC/d), hemp oil in capsules (0.47 mg THC/d), dronabinol capsules (7.5 mg THC/d), and placebo. Plasma specimens were collected during and after each dosing condition. THC and 11-OH-THC concentrations were low and never exceeded 6.1 ng/mL. Analytes were detectable 1.5 hour after initiating dosing with the 7.5 mg THC/d regimen and 4.5 hour after starting the 14.8 mg THC/d sessions. THCCOOH was detected 1.5 hour after the first dose, except for the 0.47 mg THC/d session, which required 4.5 hour for concentrations to reach the LOQ. THCCOOH concentrations peaked at 3.1 ng/mL during dosing with the low-dose hemp oils. Plasma THC and 11-OH-THC concentrations were negative for all participants at all doses within 15.5 hours after the last THC dose. Plasma THCCOOH persisted for at least 39.5 hours after the end of dosing and at much higher concentrations (up to 43.0 ng/mL). This study demonstrated that subjects who used high THC content hemp oil (347 mug/mL) as a dietary supplement had THC and metabolites in plasma in quantities comparable to those of patients using dronabinol for appetite stimulation. There was a significant correlation between body mass index and Cmax and body mass index and number of specimens positive for THC and 11-OH-THC.

An analgesic role for cannabinoids.

Cannabinoids have significant analgesic properties in animal models, particularly for chronic pain states, but there are few human studies. An endogenous cannabinoid system, with specific receptors and transmitters, has recently been discovered. This discovery has led pharmacologists to explore the potential of synthetic cannabinoids to selectively target chronic pain disorders without producing the side effects associated with cannabis. Well-controlled clinical trials on cannabinoids, and cannabinoid delivery systems, are now required.