V-PAX: Vaping THC From Electronic Cigarettes

Sponsor
University of California, San Francisco (Other)
Overall Status
Completed
CT.gov ID
NCT02955329
Collaborator
National Institutes of Health (NIH) (NIH), National Institute on Drug Abuse (NIDA) (NIH)
8
1
3
8.4
1

Study Details

Study Description

Brief Summary

This study aims to understand THC pharmacology and the safety of cannabis vaping, including the pharmacology and safety of co-administration of nicotine and THC. The study is designed as a within-subjects single-blinded crossover study. Fourteen smokers of tobacco cigarettes and cannabis will switch between three conditions, namely: (a) vaping cannabis leaf, (b) vaping tobacco containing nicotine and (c) vaping a combination of cannabis leaf and tobacco containing nicotine. All participants will vape each product with the PAX loose-leaf vaporizer. The study will be conducted during three outpatient visits separated by at least 48 hours. The order of treatment (cannabis leaf, tobacco with nicotine, cannabis leaf & tobacco with nicotine) will be counterbalanced between subjects. Subjects will be blinded to the content of the vaporizer on the study day but will be told during screening that they will vape cannabis alone, tobacco alone, and cannabis plus tobacco with nicotine.

Condition or Disease Intervention/Treatment Phase
Phase 3

Detailed Description

Electronic cigarettes (e-cigarettes) have proliferated at a rapid rate since their introduction into the US market in 2007, and their use as a form of nicotine delivery far outpaced the science base. Although the design of these devices continues to evolve, we have previously described nicotine intake, systemic retention, pharmacokinetics, and vaping behavior associated with self-administration of e-cigarettes. We demonstrated that while the shape of the plasma nicotine concentration-time curve for e-cigarettes is similar to tobacco cigarettes, the maximum plasma nicotine concentration is, on average, lower for e-cigarettes. During ad libitum access, e-cigarettes were vaped intermittently in groups of 2-5 puffs or single puffs such that plasma nicotine levels rose gradually and peaked at the end of the 90-minute session. This differs from the rapid increase in plasma nicotine observed during controlled use of e-cigarettes or during tobacco cigarette smoking. Taken together, these results indicate that e-cigarettes have the potential to produce and sustain nicotine addiction but their use and abuse liability may differ from tobacco cigarettes.

The study is designed as a within-subjects, single-blinded crossover study. Fourteen smokers of tobacco cigarettes and cannabis will switch between three conditions, namely: (a) vaping cannabis leaf, (b) vaping tobacco containing nicotine and (c) vaping a combination of cannabis leaf and tobacco containing nicotine. All participants will vape each product with the PAX loose-leaf vaporizer, which will be purchased by the study team. The cannabis leaf will be obtained through the National Institute on Drug Abuse Drug Supply Program. The tobacco-containing nicotine, used in conditions (b) and (c) will come from commercially available Marlboro brand cigarettes. The same amount of cannabis or tobacco will be used in all conditions.

The study will be conducted during three outpatient visits separated by at least 48 hours. The order of treatment (cannabis leaf, tobacco with nicotine, cannabis leaf & tobacco with nicotine) will be counterbalanced between subjects. Subjects will be blinded to the content of the vaporizer on the study day but will be told during screening that they will vape cannabis alone, tobacco alone, and cannabis plus tobacco with nicotine.

While scientists struggle to keep up with the latest electronic cigarette trends, the use of these devices for cannabis rather than nicotine is increasingly prevalent. Electronic cigarette use is not restricted to nicotine. Marijuana, the most widely used illicit drug has traditionally been combusted but the vaping of loose-leaf marijuana and THC oil has been increasing. the latest national data show that 7.6% of current marijuana users (past 30 days) and 9.9% of ever cannabis users (lifetime) administered THC through a vaporizer or electronic device (the study did not differentiate between vaporizers and electronic devices like e-cigarettes). The prevalence of vaped marijuana or THC is higher among younger adults. Prevalence of vaped marijuana/THC among 18-24 and 25-34 year-old ever marijuana users was 19.3% and 16.3%, respectively, compared to 8.8% for 35-49 year-olds and 5.7% for those 50 years and over. A recent study also showed high rates of cannabis vaping among high school students (18.0% among ever e-cigarette users). Smoking of a combination of tobacco and marijuana in cigarette form is also common, particularly in Europe. However, very little is known about the safety and pharmacokinetics of this co-administration making it a critical area of research.

Study Design

Study Type:
Interventional
Actual Enrollment :
8 participants
Allocation:
Randomized
Intervention Model:
Crossover Assignment
Masking:
Single (Participant)
Primary Purpose:
Other
Official Title:
Vaping THC From Electronic Cigarettes: a Novel Evaluation of Intake and Pharmacokinetics
Actual Study Start Date :
Mar 20, 2019
Actual Primary Completion Date :
Nov 30, 2019
Actual Study Completion Date :
Nov 30, 2019

Arms and Interventions

Arm Intervention/Treatment
Experimental: Tobacco Arm

Participants will vape tobacco leaves with nicotine out of the PAX device.

Drug: Nicotine
Participants will vape tobacco leaves with nicotine out of the PAX device.
Other Names:
  • Tobacco Leaf
  • Device: PAX Loose Leaf Vaporizer
    In all three arms, the participant will be using the same PAX electronic cigarette device. The only difference is whether the participant will be vaping nicotine only, THC only, or nicotine and THC.

    Experimental: Cannabis Arm

    Participants will vape marijuana leaves with THC (Tetrahydrocannabinol) out of the PAX device.

    Drug: Cannabis
    Participants will vape marijuana leaves with nicotine out of the PAX device.
    Other Names:
  • Marijuana Leaf
  • Device: PAX Loose Leaf Vaporizer
    In all three arms, the participant will be using the same PAX electronic cigarette device. The only difference is whether the participant will be vaping nicotine only, THC only, or nicotine and THC.

    Experimental: Combined Cannabis and Tobacco Arm

    Participants will vape flavorless 6% nicotine e-liquid, followed by THC (Tetrahydrocannabinol) out of the PAX device.

    Drug: Nicotine
    Participants will vape tobacco leaves with nicotine out of the PAX device.
    Other Names:
  • Tobacco Leaf
  • Drug: Cannabis
    Participants will vape marijuana leaves with nicotine out of the PAX device.
    Other Names:
  • Marijuana Leaf
  • Device: PAX Loose Leaf Vaporizer
    In all three arms, the participant will be using the same PAX electronic cigarette device. The only difference is whether the participant will be vaping nicotine only, THC only, or nicotine and THC.

    Outcome Measures

    Primary Outcome Measures

    1. Mean Delivered and Retained Doses [Study Day 1-3]

      Delivered Tetrahydrocannabinol (THC) and nicotine doses are estimated as the change in e-cigarette weight × concentration of THC or nicotine in e-liquid. The amount of THC or nicotine systemically retained is estimated as delivered dose minus amount in gas traps.

    2. Median Peak THC Concentration (Cmax) [Study Day 1-3]

      Median peak concentration of THC between vaped loose-leaf cannabis, mixture of cannabis and tobacco containing nicotine, and the tobacco alone treatment condition will be reported

    3. Median Peak Nicotine Concentration (Cmax) [Study Day 1-3]

      Median peak concentration of nicotine between vaped loose-leaf cannabis, mixture of cannabis and tobacco containing nicotine, and the tobacco alone treatment condition will be reported

    4. Median THC Exposure [Study Day 1-3]

      Median exposure of nicotine using area under the blood/plasma concentration-time curve(AUC) between vaped loose-leaf cannabis, mixture of cannabis and tobacco containing nicotine, and the tobacco alone treatment condition will be reported

    5. Median Nicotine Exposure [Study Day 1-3]

      Compare median exposure of nicotine using AUC (area under the blood/plasma concentration-time curve) between vaped loose-leaf tobacco containing nicotine vs. mixture of cannabis and tobacco containing nicotine.

    6. Mean Heart Rate [Study Day 1-3]

      Heart rate monitoring by pulse oximeter

    7. Mean Score on the Drug Effects Questionnaire (DEQ) [Study Day 1-3]

      The Drug Effects Questionnaire (DEQ) is widely used in studies of acute subjective response (SR) to a variety of substances which assessed the extent to which participants (1) feel any substance effect(s), (2) feel high, (3) like the effects, (4) dislike the effects, and (5) want more of the substance by instructing participants to place a mark on a 100mm vertical, visual, analog scale with scores ranging from 0 ="not at all" to 100 = "extremely" for each question. The mean of the individual responses is used to general a total score with a range from 0 to 100, with higher scores indicate a greater "liking" of the effects of the substance. The mean and standard deviation of each treatment condition will be reported.

    8. Mean Scores on the Marijuana Craving Questionnaire-Short Form (MCQ-SF) [Study Day 1-3]

      This 12-item multidimensional measure assesses cannabis craving based on 4 factors: Compulsivity, Emotionality, Expectancy, Purposefulness. Each item asks about the respondent's feelings and thoughts about smoking marijuana as he or she is completing the questionnaire (i.e., right now). Each response is scored a number ranging from 1 (strongly disagree) to 7 (strongly agree) with higher scores indicating a greater level of craving. The calculation of each subscale is as follows: Compulsivity: Mean of items 2, 7, and 10; Emotionality: Mean of items 4, 6, and 9; Expectancy: Mean of items 5, 11, and 12; Purposefulness: Mean of items 1, 3, and 8 with the minimum possible score = 1 and the maximum possible score = 7 for any subscale. The mean and standard deviation of each subscale for each treatment condition will be reported.

    9. Mean Scores on the Modified Cigarette Evaluation Questionnaire (mCEQ) [Study Day 1-3]

      The modified Cigarette Evaluation Questionnaire (mCEQ) uses three multi-item subscales and two single items: "Smoking Satisfaction" (items 1, 2, and 12);"Psychological Reward" (items 4 through 8); "Aversion" (items 9 and 10);"Enjoyment of Respiratory Tract Sensations" (item 3); and "Craving Reduction"(item 11). Scores for each subscale are calculated as the mean of the individual item responses or the single item. Higher scores indicate greater intensity on that scale. Items are rated on a seven-point scale ranging from 1 (not at all) to 7 (extremely) and total scores are averaged across all items with a minimum average score of 1 and a maximum average score of 7. Higher scores indicate greater intensity of each smoking effect with, for example, greater satisfaction or psychological reward after smoking. The mean and standard deviation for each treatment condition will be reported.

    10. Mean Scores on the Positive Affect Negative Affect Schedule (PANAS) [Study Day 1-3]

      The Positive and Negative Affect Schedule (PANAS) is a brief scale is comprised of 20 items, with 10 items measuring positive affect (e.g., excited, inspired) and 10 items measuring negative affect (e.g., upset, afraid). Each item is rated on a five-point Likert Scale, ranging from 1 = Very Slightly or Not at all to 5 = Extremely, to measure the extent to which the affect has been experienced in a specified time frame and the final score is derived out of the sum of the ten items on both the positive and negative side. Scores can range from 10-50 for both the Positive and Negative Affect with the lower scores representing lower levels of Positive/Negative Affect and higher scores representing higher levels of Positive/Negative Affect.

    11. Mean Scores on the Minnesota Nicotine Withdrawal Scale (MNWS) [Study Day 1-3]

      The Minnesota Nicotine Withdrawal Scale is an 7-item self - report scale designed to measure the severity of craving and withdrawal symptoms experienced during smoking cessation. Each item is rated on a scale of 0 to 4 with 0=none,1= Slight, 2= Mild, 3= Moderate, and 4=Severe. Seven of the items are symptoms derived from the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5) Tobacco Withdrawal diagnosis and are as follows: depression, insomnia, irritability/frustration/anger, anxiety/nervousness, difficulty concentrating, restlessness, increased appetite and at least five of seven items must have responses in order to generate a reliable score. The responses to each item are summed to produce a total withdrawal summary score with greater scores indicating a higher level of severity in nicotine withdrawal symptoms overall. The mean and standard deviation of each treatment condition will be reported with a minimum mean score of 0 and a maximum mean score of 4.

    Eligibility Criteria

    Criteria

    Ages Eligible for Study:
    21 Years to 70 Years
    Sexes Eligible for Study:
    All
    Accepts Healthy Volunteers:
    Yes

    Inclusion

    • Age >=21 years <=70 years

    • Regular user of tobacco cigarettes (daily or most days)

    • Regular user of cannabis in any form (combusted or ingested) at least 5 days out of the month.

    • Positive for Tetrahydrocannabinol (THC) on screening toxicology test

    • Willing to abstain from tobacco smoking and all other combustible products (ex: cigars) for 12 hours prior to each outpatient hospital admission.

    • Willing to abstain from smoking/ingesting cannabis for 12 hours prior to each outpatient hospital admission.

    • Willing to abstain from using any kind of nicotine products for 12 hours prior to each outpatient hospital admission (ex: electronic cigarettes, nicotine replacement therapy).

    • Saliva cotinine ≥ 30 ng/mL and/or NicAlert of 6

    • Healthy (based on limited physical examination and medical history collected during screening)

    • Heart rate < 105 beats per minute (BPM)

    • Systolic Blood Pressure < 160 and > 90 (considered out of range if both machine and manual readings are above/below these thresholds)

    • Diastolic Blood Pressure < 100 and > 50 (considered out of range if both machine and manual readings are above/below these thresholds)

    • Body Mass Index ≤<=38.0

    Exclusion

    • Medical (The following unstable medical conditions):

    • Heart disease

    • Uncontrolled hypertension

    • Thyroid disease (okay if controlled with medication)

    • Diabetes

    • Hepatitis B or C or Liver disease

    • Glaucoma

    • Prostatic hypertrophy

    • History of paranoia after marijuana use

    • Psychiatric conditions

    • Current or past schizophrenia, and/or current or past bipolar disorder

    • Adult onset Attention-deficit/hyperactivity disorder (ADHD) (if being treated)

    • Participants with current or past depression and/or anxiety disorders will be reviewed by the study physician and considered for inclusion

    • History of psychiatric hospitalizations are not exclusionary, but study participation will be determined as per study physician's approval

    • Drug/Alcohol Dependence

    • Alcohol or illicit drug dependence within the past 12 months with the exception of those who have recently completed an alcohol/drug treatment program and are currently abstaining from drug and alcohol

    • Positive toxicology test at the screening visit (THC & prescribed medications okay)

    • Methadone replacement therapy

    • Scoring a 2 or higher on the Severity of Dependence Scale for cannabis use.

    • Psychiatric medications

    • Current regular use of any psychiatric medications with the exception of Selective Serotonin Reuptake Inhibitors (SSRIs) and serotonin-norepinephrine reuptake Inhibitors (SNRIs) and current evaluation by the study physician that the participant is otherwise healthy, stable, and able to participate.

    • Other Medications

    • Use of medications that are inducers of nicotine metabolizing enzyme CYP2A6 (Example: rifampicin, dexamethasone, phenobarbital, and other anticonvulsant drugs).

    • Concurrent use of nicotine-containing medications

    • Other/Misc. Chronic Health Conditions

    • Oral thrush

    • Fainting

    • Untreated thyroid disease

    • Other "life threatening illnesses" as per study physician's discretion

    • Use of Other Tobacco Products (OTP); any of the following products in combination more than 15 times in the past month

    • smokeless tobacco

    • pipes

    • cigars, cigarillos

    • blunts, spliffs

    • Pregnancy

    • Pregnancy (self-reported and urine pregnancy test)

    • Breastfeeding (determined by self-report)

    • Concurrent participation in another clinical trial

    • Inability to communicate in English

    • Planning to quit smoking or cannabis use within the next 60 days

    Contacts and Locations

    Locations

    Site City State Country Postal Code
    1 Zuckerberg San Francisco General Hospital San Francisco California United States 94110

    Sponsors and Collaborators

    • University of California, San Francisco
    • National Institutes of Health (NIH)
    • National Institute on Drug Abuse (NIDA)

    Investigators

    • Principal Investigator: Neal L Benowitz, MD, University of California, San Francisco

    Study Documents (Full-Text)

    More Information

    Publications

    Responsible Party:
    University of California, San Francisco
    ClinicalTrials.gov Identifier:
    NCT02955329
    Other Study ID Numbers:
    • 18-24854
    • 3R01DA039264-02S1
    First Posted:
    Nov 4, 2016
    Last Update Posted:
    Apr 30, 2021
    Last Verified:
    Apr 1, 2021
    Individual Participant Data (IPD) Sharing Statement:
    No
    Plan to Share IPD:
    No
    Studies a U.S. FDA-regulated Drug Product:
    Yes
    Studies a U.S. FDA-regulated Device Product:
    Yes
    Keywords provided by University of California, San Francisco
    Additional relevant MeSH terms:

    Study Results

    Participant Flow

    Recruitment Details
    Pre-assignment Detail A total of 8 total participants received all 3 interventions over the course of 3 days, with the sequence of the interventions varied for each participant. The order of treatment (cannabis leaf, tobacco with nicotine, cannabis leaf & tobacco with nicotine) will be counterbalanced between subjects
    Arm/Group Title All Participants
    Arm/Group Description All participants were enrolled and received each of the interventions in a different order. Each intervention lasted 1 day.
    Period Title: Tobacco Arm
    STARTED 8
    COMPLETED 8
    NOT COMPLETED 0
    Period Title: Tobacco Arm
    STARTED 8
    COMPLETED 8
    NOT COMPLETED 0
    Period Title: Tobacco Arm
    STARTED 8
    COMPLETED 8
    NOT COMPLETED 0

    Baseline Characteristics

    Arm/Group Title All Participants
    Arm/Group Description All participants were enrolled and received each of the interventions in a different order. Each intervention lasted 1 day.
    Overall Participants 8
    Age (Count of Participants)
    <=18 years
    0
    0%
    Between 18 and 65 years
    8
    100%
    >=65 years
    0
    0%
    Sex: Female, Male (Count of Participants)
    Female
    1
    12.5%
    Male
    7
    87.5%
    Race (NIH/OMB) (Count of Participants)
    American Indian or Alaska Native
    0
    0%
    Asian
    0
    0%
    Native Hawaiian or Other Pacific Islander
    0
    0%
    Black or African American
    2
    25%
    White
    3
    37.5%
    More than one race
    3
    37.5%
    Unknown or Not Reported
    0
    0%
    Region of Enrollment (participants) [Number]
    United States
    8
    100%

    Outcome Measures

    1. Primary Outcome
    Title Mean Delivered and Retained Doses
    Description Delivered Tetrahydrocannabinol (THC) and nicotine doses are estimated as the change in e-cigarette weight × concentration of THC or nicotine in e-liquid. The amount of THC or nicotine systemically retained is estimated as delivered dose minus amount in gas traps.
    Time Frame Study Day 1-3

    Outcome Measure Data

    Analysis Population Description
    [Not Specified]
    Arm/Group Title Tobacco Arm Cannabis Arm Combined Cannabis and Tobacco Arm
    Arm/Group Description Participants will vape tobacco leaves with nicotine out of the PAX device. Nicotine: Participants will vape tobacco leaves with nicotine out of the PAX device. PAX Loose Leaf Vaporizer: In all three arms, the participant will be using the same PAX electronic cigarette device. The only difference is whether the participant will be vaping nicotine only, THC only, or nicotine and THC. Participants will vape marijuana leaves with THC (Tetrahydrocannabinol) out of the PAX device. Cannabis: Participants will vape marijuana leaves with nicotine out of the PAX device. PAX Loose Leaf Vaporizer: In all three arms, the participant will be using the same PAX electronic cigarette device. The only difference is whether the participant will be vaping nicotine only, THC only, or nicotine and THC. Participants will vape flavorless 6% nicotine e-liquid, followed by THC (Tetrahydrocannabinol) out of the PAX device. Nicotine: Participants will vape tobacco leaves with nicotine out of the PAX device. Cannabis: Participants will vape marijuana leaves with nicotine out of the PAX device. PAX Loose Leaf Vaporizer: In all three arms, the participant will be using the same PAX electronic cigarette device. The only difference is whether the participant will be vaping nicotine only, THC only, or nicotine and THC.
    Measure Participants 8 8 8
    Mean (Standard Deviation) [grams (g)]
    0.016
    (0.003)
    0.018
    (0.008)
    0.026
    (0.008)
    2. Primary Outcome
    Title Median Peak THC Concentration (Cmax)
    Description Median peak concentration of THC between vaped loose-leaf cannabis, mixture of cannabis and tobacco containing nicotine, and the tobacco alone treatment condition will be reported
    Time Frame Study Day 1-3

    Outcome Measure Data

    Analysis Population Description
    [Not Specified]
    Arm/Group Title Tobacco Arm Cannabis Arm Combined Cannabis and Tobacco Arm
    Arm/Group Description Participants will vape tobacco leaves with nicotine out of the PAX device. Nicotine: Participants will vape tobacco leaves with nicotine out of the PAX device. PAX Loose Leaf Vaporizer: In all three arms, the participant will be using the same PAX electronic cigarette device. The only difference is whether the participant will be vaping nicotine only, THC only, or nicotine and THC. Participants will vape marijuana leaves with THC (Tetrahydrocannabinol) out of the PAX device. Cannabis: Participants will vape marijuana leaves with nicotine out of the PAX device. PAX Loose Leaf Vaporizer: In all three arms, the participant will be using the same PAX electronic cigarette device. The only difference is whether the participant will be vaping nicotine only, THC only, or nicotine and THC. Participants will vape flavorless 6% nicotine e-liquid, followed by THC (Tetrahydrocannabinol) out of the PAX device. Nicotine: Participants will vape tobacco leaves with nicotine out of the PAX device. Cannabis: Participants will vape marijuana leaves with nicotine out of the PAX device. PAX Loose Leaf Vaporizer: In all three arms, the participant will be using the same PAX electronic cigarette device. The only difference is whether the participant will be vaping nicotine only, THC only, or nicotine and THC.
    Measure Participants 8 8 8
    Median (Inter-Quartile Range) [mg/mL]
    1.52
    9.72
    25.74
    3. Primary Outcome
    Title Median Peak Nicotine Concentration (Cmax)
    Description Median peak concentration of nicotine between vaped loose-leaf cannabis, mixture of cannabis and tobacco containing nicotine, and the tobacco alone treatment condition will be reported
    Time Frame Study Day 1-3

    Outcome Measure Data

    Analysis Population Description
    [Not Specified]
    Arm/Group Title Tobacco Arm Cannabis Arm Combined Cannabis and Tobacco Arm
    Arm/Group Description Participants will vape tobacco leaves with nicotine out of the PAX device. Nicotine: Participants will vape tobacco leaves with nicotine out of the PAX device. PAX Loose Leaf Vaporizer: In all three arms, the participant will be using the same PAX electronic cigarette device. The only difference is whether the participant will be vaping nicotine only, THC only, or nicotine and THC. Participants will vape marijuana leaves with THC (Tetrahydrocannabinol) out of the PAX device. Cannabis: Participants will vape marijuana leaves with nicotine out of the PAX device. PAX Loose Leaf Vaporizer: In all three arms, the participant will be using the same PAX electronic cigarette device. The only difference is whether the participant will be vaping nicotine only, THC only, or nicotine and THC. Participants will vape flavorless 6% nicotine e-liquid, followed by THC (Tetrahydrocannabinol) out of the PAX device. Nicotine: Participants will vape tobacco leaves with nicotine out of the PAX device. Cannabis: Participants will vape marijuana leaves with nicotine out of the PAX device. PAX Loose Leaf Vaporizer: In all three arms, the participant will be using the same PAX electronic cigarette device. The only difference is whether the participant will be vaping nicotine only, THC only, or nicotine and THC.
    Measure Participants 8 8 8
    Median (Inter-Quartile Range) [ng/mL]
    0.55
    0.38
    1.59
    4. Primary Outcome
    Title Median THC Exposure
    Description Median exposure of nicotine using area under the blood/plasma concentration-time curve(AUC) between vaped loose-leaf cannabis, mixture of cannabis and tobacco containing nicotine, and the tobacco alone treatment condition will be reported
    Time Frame Study Day 1-3

    Outcome Measure Data

    Analysis Population Description
    [Not Specified]
    Arm/Group Title Tobacco Arm Cannabis Arm Combined Cannabis and Tobacco Arm
    Arm/Group Description Participants will vape tobacco leaves with nicotine out of the PAX device. Nicotine: Participants will vape tobacco leaves with nicotine out of the PAX device. PAX Loose Leaf Vaporizer: In all three arms, the participant will be using the same PAX electronic cigarette device. The only difference is whether the participant will be vaping nicotine only, THC only, or nicotine and THC. Participants will vape marijuana leaves with THC (Tetrahydrocannabinol) out of the PAX device. Cannabis: Participants will vape marijuana leaves with nicotine out of the PAX device. PAX Loose Leaf Vaporizer: In all three arms, the participant will be using the same PAX electronic cigarette device. The only difference is whether the participant will be vaping nicotine only, THC only, or nicotine and THC. Participants will vape flavorless 6% nicotine e-liquid, followed by THC (Tetrahydrocannabinol) out of the PAX device. Nicotine: Participants will vape tobacco leaves with nicotine out of the PAX device. Cannabis: Participants will vape marijuana leaves with nicotine out of the PAX device. PAX Loose Leaf Vaporizer: In all three arms, the participant will be using the same PAX electronic cigarette device. The only difference is whether the participant will be vaping nicotine only, THC only, or nicotine and THC.
    Measure Participants 8 8 8
    Median (Inter-Quartile Range) [ng/mL•minute]
    201.6
    306.4
    585.6
    5. Primary Outcome
    Title Median Nicotine Exposure
    Description Compare median exposure of nicotine using AUC (area under the blood/plasma concentration-time curve) between vaped loose-leaf tobacco containing nicotine vs. mixture of cannabis and tobacco containing nicotine.
    Time Frame Study Day 1-3

    Outcome Measure Data

    Analysis Population Description
    [Not Specified]
    Arm/Group Title Tobacco Arm Cannabis Arm Combined Cannabis and Tobacco Arm
    Arm/Group Description Participants will vape tobacco leaves with nicotine out of the PAX device. Nicotine: Participants will vape tobacco leaves with nicotine out of the PAX device. PAX Loose Leaf Vaporizer: In all three arms, the participant will be using the same PAX electronic cigarette device. The only difference is whether the participant will be vaping nicotine only, THC only, or nicotine and THC. Participants will vape marijuana leaves with THC (Tetrahydrocannabinol) out of the PAX device. Cannabis: Participants will vape marijuana leaves with nicotine out of the PAX device. PAX Loose Leaf Vaporizer: In all three arms, the participant will be using the same PAX electronic cigarette device. The only difference is whether the participant will be vaping nicotine only, THC only, or nicotine and THC. Participants will vape flavorless 6% nicotine e-liquid, followed by THC (Tetrahydrocannabinol) out of the PAX device. Nicotine: Participants will vape tobacco leaves with nicotine out of the PAX device. Cannabis: Participants will vape marijuana leaves with nicotine out of the PAX device. PAX Loose Leaf Vaporizer: In all three arms, the participant will be using the same PAX electronic cigarette device. The only difference is whether the participant will be vaping nicotine only, THC only, or nicotine and THC.
    Measure Participants 8 8 8
    Median (Inter-Quartile Range) [ng/mL•minute]
    63.1
    42.7
    134.9
    6. Primary Outcome
    Title Mean Heart Rate
    Description Heart rate monitoring by pulse oximeter
    Time Frame Study Day 1-3

    Outcome Measure Data

    Analysis Population Description
    [Not Specified]
    Arm/Group Title Tobacco Arm Cannabis Arm Combined Cannabis and Tobacco Arm
    Arm/Group Description Participants will vape tobacco leaves with nicotine out of the PAX device. Nicotine: Participants will vape tobacco leaves with nicotine out of the PAX device. PAX Loose Leaf Vaporizer: In all three arms, the participant will be using the same PAX electronic cigarette device. The only difference is whether the participant will be vaping nicotine only, THC only, or nicotine and THC. Participants will vape marijuana leaves with THC (Tetrahydrocannabinol) out of the PAX device. Cannabis: Participants will vape marijuana leaves with nicotine out of the PAX device. PAX Loose Leaf Vaporizer: In all three arms, the participant will be using the same PAX electronic cigarette device. The only difference is whether the participant will be vaping nicotine only, THC only, or nicotine and THC. Participants will vape flavorless 6% nicotine e-liquid, followed by THC (Tetrahydrocannabinol) out of the PAX device. Nicotine: Participants will vape tobacco leaves with nicotine out of the PAX device. Cannabis: Participants will vape marijuana leaves with nicotine out of the PAX device. PAX Loose Leaf Vaporizer: In all three arms, the participant will be using the same PAX electronic cigarette device. The only difference is whether the participant will be vaping nicotine only, THC only, or nicotine and THC.
    Measure Participants 8 8 8
    Mean (95% Confidence Interval) [bpm]
    67.3
    66.8
    70.5
    7. Primary Outcome
    Title Mean Score on the Drug Effects Questionnaire (DEQ)
    Description The Drug Effects Questionnaire (DEQ) is widely used in studies of acute subjective response (SR) to a variety of substances which assessed the extent to which participants (1) feel any substance effect(s), (2) feel high, (3) like the effects, (4) dislike the effects, and (5) want more of the substance by instructing participants to place a mark on a 100mm vertical, visual, analog scale with scores ranging from 0 ="not at all" to 100 = "extremely" for each question. The mean of the individual responses is used to general a total score with a range from 0 to 100, with higher scores indicate a greater "liking" of the effects of the substance. The mean and standard deviation of each treatment condition will be reported.
    Time Frame Study Day 1-3

    Outcome Measure Data

    Analysis Population Description
    [Not Specified]
    Arm/Group Title Tobacco Arm Cannabis Arm Combined Cannabis and Tobacco Arm
    Arm/Group Description Participants will vape tobacco leaves with nicotine out of the PAX device. Nicotine: Participants will vape tobacco leaves with nicotine out of the PAX device. PAX Loose Leaf Vaporizer: In all three arms, the participant will be using the same PAX electronic cigarette device. The only difference is whether the participant will be vaping nicotine only, THC only, or nicotine and THC. Participants will vape marijuana leaves with THC (Tetrahydrocannabinol) out of the PAX device. Cannabis: Participants will vape marijuana leaves with nicotine out of the PAX device. PAX Loose Leaf Vaporizer: In all three arms, the participant will be using the same PAX electronic cigarette device. The only difference is whether the participant will be vaping nicotine only, THC only, or nicotine and THC. Participants will vape flavorless 6% nicotine e-liquid, followed by THC (Tetrahydrocannabinol) out of the PAX device. Nicotine: Participants will vape tobacco leaves with nicotine out of the PAX device. Cannabis: Participants will vape marijuana leaves with nicotine out of the PAX device. PAX Loose Leaf Vaporizer: In all three arms, the participant will be using the same PAX electronic cigarette device. The only difference is whether the participant will be vaping nicotine only, THC only, or nicotine and THC.
    Measure Participants 8 8 8
    Mean (Standard Deviation) [score on a scale]
    45.4
    (33.7)
    69.0
    (16.7)
    73.2
    (14.4)
    8. Primary Outcome
    Title Mean Scores on the Marijuana Craving Questionnaire-Short Form (MCQ-SF)
    Description This 12-item multidimensional measure assesses cannabis craving based on 4 factors: Compulsivity, Emotionality, Expectancy, Purposefulness. Each item asks about the respondent's feelings and thoughts about smoking marijuana as he or she is completing the questionnaire (i.e., right now). Each response is scored a number ranging from 1 (strongly disagree) to 7 (strongly agree) with higher scores indicating a greater level of craving. The calculation of each subscale is as follows: Compulsivity: Mean of items 2, 7, and 10; Emotionality: Mean of items 4, 6, and 9; Expectancy: Mean of items 5, 11, and 12; Purposefulness: Mean of items 1, 3, and 8 with the minimum possible score = 1 and the maximum possible score = 7 for any subscale. The mean and standard deviation of each subscale for each treatment condition will be reported.
    Time Frame Study Day 1-3

    Outcome Measure Data

    Analysis Population Description
    [Not Specified]
    Arm/Group Title Tobacco Arm Cannabis Arm Combined Cannabis and Tobacco Arm
    Arm/Group Description Participants will vape tobacco leaves with nicotine out of the PAX device. Nicotine: Participants will vape tobacco leaves with nicotine out of the PAX device. PAX Loose Leaf Vaporizer: In all three arms, the participant will be using the same PAX electronic cigarette device. The only difference is whether the participant will be vaping nicotine only, THC only, or nicotine and THC. Participants will vape marijuana leaves with THC (Tetrahydrocannabinol) out of the PAX device. Cannabis: Participants will vape marijuana leaves with nicotine out of the PAX device. PAX Loose Leaf Vaporizer: In all three arms, the participant will be using the same PAX electronic cigarette device. The only difference is whether the participant will be vaping nicotine only, THC only, or nicotine and THC. Participants will vape flavorless 6% nicotine e-liquid, followed by THC (Tetrahydrocannabinol) out of the PAX device. Nicotine: Participants will vape tobacco leaves with nicotine out of the PAX device. Cannabis: Participants will vape marijuana leaves with nicotine out of the PAX device. PAX Loose Leaf Vaporizer: In all three arms, the participant will be using the same PAX electronic cigarette device. The only difference is whether the participant will be vaping nicotine only, THC only, or nicotine and THC.
    Measure Participants 8 8 8
    Compulsivity
    2.8
    (1.7)
    3.0
    (1.8)
    2.5
    (1.6)
    Emotionality
    3.1
    (2.1)
    3.5
    (1.8)
    2.9
    (1.9)
    Expectancy
    4.1
    (1.8)
    4.6
    (1.8)
    3.9
    (1.6)
    Purposefulness
    4.6
    (1.8)
    4.8
    (2.2)
    4.0
    (2.3)
    9. Primary Outcome
    Title Mean Scores on the Modified Cigarette Evaluation Questionnaire (mCEQ)
    Description The modified Cigarette Evaluation Questionnaire (mCEQ) uses three multi-item subscales and two single items: "Smoking Satisfaction" (items 1, 2, and 12);"Psychological Reward" (items 4 through 8); "Aversion" (items 9 and 10);"Enjoyment of Respiratory Tract Sensations" (item 3); and "Craving Reduction"(item 11). Scores for each subscale are calculated as the mean of the individual item responses or the single item. Higher scores indicate greater intensity on that scale. Items are rated on a seven-point scale ranging from 1 (not at all) to 7 (extremely) and total scores are averaged across all items with a minimum average score of 1 and a maximum average score of 7. Higher scores indicate greater intensity of each smoking effect with, for example, greater satisfaction or psychological reward after smoking. The mean and standard deviation for each treatment condition will be reported.
    Time Frame Study Day 1-3

    Outcome Measure Data

    Analysis Population Description
    [Not Specified]
    Arm/Group Title Tobacco Arm Cannabis Arm Combined Cannabis and Tobacco Arm
    Arm/Group Description Participants will vape tobacco leaves with nicotine out of the PAX device. Nicotine: Participants will vape tobacco leaves with nicotine out of the PAX device. PAX Loose Leaf Vaporizer: In all three arms, the participant will be using the same PAX electronic cigarette device. The only difference is whether the participant will be vaping nicotine only, THC only, or nicotine and THC. Participants will vape marijuana leaves with THC (Tetrahydrocannabinol) out of the PAX device. Cannabis: Participants will vape marijuana leaves with nicotine out of the PAX device. PAX Loose Leaf Vaporizer: In all three arms, the participant will be using the same PAX electronic cigarette device. The only difference is whether the participant will be vaping nicotine only, THC only, or nicotine and THC. Participants will vape flavorless 6% nicotine e-liquid, followed by THC (Tetrahydrocannabinol) out of the PAX device. Nicotine: Participants will vape tobacco leaves with nicotine out of the PAX device. Cannabis: Participants will vape marijuana leaves with nicotine out of the PAX device. PAX Loose Leaf Vaporizer: In all three arms, the participant will be using the same PAX electronic cigarette device. The only difference is whether the participant will be vaping nicotine only, THC only, or nicotine and THC.
    Measure Participants 8 8 8
    Mean (Standard Deviation) [score on a scale]
    1.5
    (3.2)
    3.1
    (3.5)
    1.4
    (1.5)
    10. Primary Outcome
    Title Mean Scores on the Positive Affect Negative Affect Schedule (PANAS)
    Description The Positive and Negative Affect Schedule (PANAS) is a brief scale is comprised of 20 items, with 10 items measuring positive affect (e.g., excited, inspired) and 10 items measuring negative affect (e.g., upset, afraid). Each item is rated on a five-point Likert Scale, ranging from 1 = Very Slightly or Not at all to 5 = Extremely, to measure the extent to which the affect has been experienced in a specified time frame and the final score is derived out of the sum of the ten items on both the positive and negative side. Scores can range from 10-50 for both the Positive and Negative Affect with the lower scores representing lower levels of Positive/Negative Affect and higher scores representing higher levels of Positive/Negative Affect.
    Time Frame Study Day 1-3

    Outcome Measure Data

    Analysis Population Description
    [Not Specified]
    Arm/Group Title Tobacco Arm Cannabis Arm Combined Cannabis and Tobacco Arm
    Arm/Group Description Participants will vape tobacco leaves with nicotine out of the PAX device. Nicotine: Participants will vape tobacco leaves with nicotine out of the PAX device. PAX Loose Leaf Vaporizer: In all three arms, the participant will be using the same PAX electronic cigarette device. The only difference is whether the participant will be vaping nicotine only, THC only, or nicotine and THC. Participants will vape marijuana leaves with THC (Tetrahydrocannabinol) out of the PAX device. Cannabis: Participants will vape marijuana leaves with nicotine out of the PAX device. PAX Loose Leaf Vaporizer: In all three arms, the participant will be using the same PAX electronic cigarette device. The only difference is whether the participant will be vaping nicotine only, THC only, or nicotine and THC. Participants will vape flavorless 6% nicotine e-liquid, followed by THC (Tetrahydrocannabinol) out of the PAX device. Nicotine: Participants will vape tobacco leaves with nicotine out of the PAX device. Cannabis: Participants will vape marijuana leaves with nicotine out of the PAX device. PAX Loose Leaf Vaporizer: In all three arms, the participant will be using the same PAX electronic cigarette device. The only difference is whether the participant will be vaping nicotine only, THC only, or nicotine and THC.
    Measure Participants 8 8 8
    Positive
    26.9
    (11.6)
    23.0
    (9.6)
    25.8
    (11.1)
    Negative
    10.6
    (1.2)
    11.4
    (3.1)
    10.2
    (0.7)
    11. Primary Outcome
    Title Mean Scores on the Minnesota Nicotine Withdrawal Scale (MNWS)
    Description The Minnesota Nicotine Withdrawal Scale is an 7-item self - report scale designed to measure the severity of craving and withdrawal symptoms experienced during smoking cessation. Each item is rated on a scale of 0 to 4 with 0=none,1= Slight, 2= Mild, 3= Moderate, and 4=Severe. Seven of the items are symptoms derived from the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5) Tobacco Withdrawal diagnosis and are as follows: depression, insomnia, irritability/frustration/anger, anxiety/nervousness, difficulty concentrating, restlessness, increased appetite and at least five of seven items must have responses in order to generate a reliable score. The responses to each item are summed to produce a total withdrawal summary score with greater scores indicating a higher level of severity in nicotine withdrawal symptoms overall. The mean and standard deviation of each treatment condition will be reported with a minimum mean score of 0 and a maximum mean score of 4.
    Time Frame Study Day 1-3

    Outcome Measure Data

    Analysis Population Description
    [Not Specified]
    Arm/Group Title Tobacco Arm Cannabis Arm Combined Cannabis and Tobacco Arm
    Arm/Group Description Participants will vape tobacco leaves with nicotine out of the PAX device. Nicotine: Participants will vape tobacco leaves with nicotine out of the PAX device. PAX Loose Leaf Vaporizer: In all three arms, the participant will be using the same PAX electronic cigarette device. The only difference is whether the participant will be vaping nicotine only, THC only, or nicotine and THC. Participants will vape marijuana leaves with THC (Tetrahydrocannabinol) out of the PAX device. Cannabis: Participants will vape marijuana leaves with nicotine out of the PAX device. PAX Loose Leaf Vaporizer: In all three arms, the participant will be using the same PAX electronic cigarette device. The only difference is whether the participant will be vaping nicotine only, THC only, or nicotine and THC. Participants will vape flavorless 6% nicotine e-liquid, followed by THC (Tetrahydrocannabinol) out of the PAX device. Nicotine: Participants will vape tobacco leaves with nicotine out of the PAX device. Cannabis: Participants will vape marijuana leaves with nicotine out of the PAX device. PAX Loose Leaf Vaporizer: In all three arms, the participant will be using the same PAX electronic cigarette device. The only difference is whether the participant will be vaping nicotine only, THC only, or nicotine and THC.
    Measure Participants 8 8 8
    Mean (Standard Deviation) [score on a scale]
    0.8
    (1.0)
    1.2
    (1.2)
    0.9
    (1.1)

    Adverse Events

    Time Frame 3 days
    Adverse Event Reporting Description
    Arm/Group Title Tobacco Arm Cannabis Arm Combined Cannabis and Tobacco Arm
    Arm/Group Description Participants will vape tobacco leaves with nicotine out of the PAX device. Nicotine: Participants will vape tobacco leaves with nicotine out of the PAX device. PAX Loose Leaf Vaporizer: In all three arms, the participant will be using the same PAX electronic cigarette device. The only difference is whether the participant will be vaping nicotine only, THC only, or nicotine and THC. Participants will vape marijuana leaves with THC (Tetrahydrocannabinol) out of the PAX device. Cannabis: Participants will vape marijuana leaves with nicotine out of the PAX device. PAX Loose Leaf Vaporizer: In all three arms, the participant will be using the same PAX electronic cigarette device. The only difference is whether the participant will be vaping nicotine only, THC only, or nicotine and THC. Participants will vape flavorless 6% nicotine e-liquid, followed by THC (Tetrahydrocannabinol) out of the PAX device. Nicotine: Participants will vape tobacco leaves with nicotine out of the PAX device. Cannabis: Participants will vape marijuana leaves with nicotine out of the PAX device. PAX Loose Leaf Vaporizer: In all three arms, the participant will be using the same PAX electronic cigarette device. The only difference is whether the participant will be vaping nicotine only, THC only, or nicotine and THC.
    All Cause Mortality
    Tobacco Arm Cannabis Arm Combined Cannabis and Tobacco Arm
    Affected / at Risk (%) # Events Affected / at Risk (%) # Events Affected / at Risk (%) # Events
    Total 0/8 (0%) 0/8 (0%) 0/8 (0%)
    Serious Adverse Events
    Tobacco Arm Cannabis Arm Combined Cannabis and Tobacco Arm
    Affected / at Risk (%) # Events Affected / at Risk (%) # Events Affected / at Risk (%) # Events
    Total 0/8 (0%) 0/8 (0%) 0/8 (0%)
    Other (Not Including Serious) Adverse Events
    Tobacco Arm Cannabis Arm Combined Cannabis and Tobacco Arm
    Affected / at Risk (%) # Events Affected / at Risk (%) # Events Affected / at Risk (%) # Events
    Total 0/8 (0%) 0/8 (0%) 0/8 (0%)

    Limitations/Caveats

    [Not Specified]

    More Information

    Certain Agreements

    All Principal Investigators ARE employed by the organization sponsoring the study.

    There is NOT an agreement between Principal Investigators and the Sponsor (or its agents) that restricts the PI's rights to discuss or publish trial results after the trial is completed.

    Results Point of Contact

    Name/Title Dr. Gideon St. Helen
    Organization University of California, San Francisco
    Phone 628-206-2687
    Email gideon.sthelen@ucsf.edu
    Responsible Party:
    University of California, San Francisco
    ClinicalTrials.gov Identifier:
    NCT02955329
    Other Study ID Numbers:
    • 18-24854
    • 3R01DA039264-02S1
    First Posted:
    Nov 4, 2016
    Last Update Posted:
    Apr 30, 2021
    Last Verified:
    Apr 1, 2021