THCPhase 2CANNICNCT05999383
Understanding the Clinical Pharmacology of Marijuana-Tobacco Co-administration
A Phase 2 study testing Cannabis, Nicotine and Pax Loose Leaf Vaporizer in people with THC and Cannabis, run by University of California, San Francisco at 1 site in United States.
Trial summary
This is a crossover, randomized, double-blinded clinical pharmacology study enrolling dual cannabis-tobacco smokers to better understand the combined effects of co-administering cannabis and tobacco. Read more about this study
- Who is it for?
- Ages 21 to 65 yearsHealthy volunteers can take part
- Conditions the study is for
- THC, Cannabis, Cannabis Use
- What is being tested?
- Cannabis, Nicotine and Pax Loose Leaf Vaporizer
- Type of treatment
- Medical device
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 48 participants
- Where
- 1 siteUnited States
- Study dates
- 1 Jul 2025to 1 Feb 2028
- Phase
- Phase 2
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 21 to 65 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Heart rate < 105 beats per minute (BPM)*
- Systolic Blood Pressure < 160 and > 90*
- Diastolic Blood Pressure < 100 and > 50*
- Considered out of range if both machine and manual readings are above/below these thresholds.
- Body Mass Index (BMI) ≤ 38.0 (at investigator's discretion for higher BMI if no other concurrent health issues)
- Current regular user of cannabis who smokes or vapes cannabis or THC extracts at least three days a week for the past 3 months or more
Show all 9Show fewer
- Test positive for D-9-tetrahydrocannabinol (THC) at screening and self-report of cannabis use
- Current user of inhaled forms of tobacco/nicotine (cigarette, cigars, e-cigarettes) who use the product daily for the past 3 months or more
- Saliva cotinine ≥ 30 ng/mL
Who cannot join
- Unstable medical conditions:
- Heart disease
- Seizures
- Cancer
- Thyroid disease (okay if controlled with medication)
- Diabetes
Show all 48Show fewer
- Hepatitis B or C or Liver disease
- Glaucoma
- Kidney disease or urinary retention
- An ulcer in the past year
- Active use of an inhaler for asthma or Chronic Obstructive Pulmonary Disease (COPD)
- Hypertension if uncontrolled (meaning participant has a diagnosis, but they are not taking medication/under treatment (e.g., diet or exercise plan)
- Drug/Alcohol Dependence
- Alcohol or illicit drug dependence within the past 12 months (currently in treatment) with the exception of those who recently completed an alcohol/drug treatment program
- Positive toxicology test at the screening visit (THC \& prescribed medications okay)
- Opioid replacement therapy (including methadone, buprenorphine, or other)
- Psychiatric conditions
- Current or past schizophrenia, and/or current or past bipolar disorder
- Major depression, current or within the past year
- Major personality disorder
- Participants with current or past minor or moderate depression and/or anxiety disorders will be reviewed by the PI [study physician] and considered for inclusion
- History of psychiatric hospitalizations are not exclusionary, but study participation will be determined as per PI's [study physician's] approval
- Current regular use of any psychiatric medications with the exception of Selective serotonin reuptake inhibitors (SSRI) and serotonin-norepinephrine reuptake inhibitors (SNRI) and current evaluation by the PI that the participant is otherwise healthy, stable, and able to participate
- Congenital or acquired immunodeficiency disorders (i.e. HIV, congenital immune deficiency syndrome, chronic diseases)
- Other disorders (i.e. ICU, malnutrition, immunosuppressive therapy)
- Traumatic brain injury
- Recent onset or change (worsening) in cough, fever and/or abdominal symptoms (vomiting or pain) in the past two weeks
- 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
- Any stimulant medications (ex. Adderall) generally given for attention deficit hyperactivity disorder (ADHD) treatment
- Other/Misc. Chronic Health Problems
- Oral thrush
- Fainting
- Other "life threatening illnesses" as per study physician's discretion
- Pregnancy
- Pregnancy (self-reported and urine pregnancy test)
- Breastfeeding (determined by self-report)
- Concurrent participation in another clinical trial
- Inability to communicate in English
- History of marijuana-induced psychosis or paranoia after smoking marijuana
- Scoring a 7 or higher on the Severity of Dependence Scale (SDS) for cannabis use
- Planning to quit smoking or vaping within the next 60 days
- Planning to quit cannabis use within the next 60 days
- Uncomfortable with getting blood drawn
- Willingness to abstain from tobacco smoking and all combustible products for 13 hours before admission
- Willingness to abstain from smoking/ingestion of cannabis 13 hours before
- Willingness to abstain from nicotine products 13 hours before each admission
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site, 1 recruiting
- Recruiting
Zuckerberg San Francisco General Hospital
San Francisco, California, 94110
Lisa Lawrence, Lisa.Lawrence@ucsf.edu
Gideon St. Helen, PhD
About this study
This is a crossover, randomized, double-blinded clinical pharmacology study enrolling dual cannabis-tobacco smokers to better understand the combined effects of co-administering cannabis and tobacco. The project aims to describe the pharmacokinetics and pharmacodynamics of marijuana-tobacco co-administration by delivering THC and nicotine in various combinations. This foundational study will establish a research program focused on elucidating the public health consequences of marijuana-tobacco co-use.
Read the detailed description
This is a single-center, within-subject (crossover), randomized, double-blinded clinical pharmacology study of over 8 study visits (days). Participants will be non-treatment-seeking, healthy frequent users of both marijuana and tobacco/nicotine, age 21 to 65 years (21 years because of California tobacco control law). Participants will be marijuana users of any race who smoke or vape marijuana or THC extracts at least three days a week for the past 3 months or more. The study investigators will use positive urine toxicology THC results and self-report of marijuana smoking/vaping to determine eligibility. Participants must also be current users of inhaled forms of tobacco/nicotine (cigarettes, cigars, e-cigarettes) who use the product daily over the past 3 months.
Each study day will consist of a standardized session of 5 puffs of one of 8 study conditions using a PAX-3 vaporizer (PAX Labs, Inc.). Blood will be sampled multiple times for plasma THC, nicotine, and catecholamines, questionnaires administered for sensory and subjective effects, and heart rate, skin blood flow, and skin temperature will be measured. After 6 hours of abstinence, participants will have 60 minutes of ad libitum access to the assigned study condition, during which heart rate and blood pressure will be continuously monitored, blood sampled before and after for THC, nicotine, and platelet aggregation measured, and questionnaires administered.
Studies will be conducted at the Clinical \& Translational Science Institute (CTSI) Clinical Research Services-supported research ward at Zuckerberg San Francisco General.
- Conditions
- THC, Cannabis, Cannabis Use, Cannabis Smoking, Tobacco Use, Vaping
- Being tested
- Cannabis, Nicotine, Pax Loose Leaf Vaporizer, Placebo Marijuana
- Keywords
- THC, Cannabis, Marijuana, Nicotine, Vape
- Medical subject headings
- Marijuana Abuse, Marijuana Smoking, Tobacco Use, Vaping
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
CannabisDrug
Also called Marijuana
Participants will vape marijuana in varying doses from the PAX device
NicotineDrug
Also called Nicotine product
Participants will vape Regular and Very Low Nicotine content cigarettes from the PAX device
Pax Loose Leaf VaporizerDevice
Also called Electronic vaporizor
In all arms, participants will be using the PAX Loose Leave Vaporizer.
Placebo MarijuanaOther
Also called Placebo for Marijuana
Participants will vape placebo marijuana from the PAX device
| Study group | Role | What they receive |
|---|---|---|
| Placebo marijuana and regular cigarette | Experimental | Participants will vape a 50/50 mixture of placebo marijuana (0% THC) and regular cigarette (25.94 mg/g nicotine content) Receives: Drug: Nicotine; Device: Pax Loose Leaf Vaporizer; Other: Placebo Marijuana |
| Placebo marijuana and Very Low Nicotine Content cigarette | Experimental | Participants will vape a 50/50 mixture of placebo marijuana (0% THC) and Very Low Nicotine Content cigarette (0.42 mg/g nicotine content) Receives: Drug: Nicotine; Device: Pax Loose Leaf Vaporizer; Other: Placebo Marijuana |
| Medium marijuana and regular cigarette | Experimental | Participants will vape a 50/50 mixture of medium marijuana (<5% THC) and regular cigarette (25.94 mg/g nicotine content) Receives: Drug: Cannabis; Drug: Nicotine; Device: Pax Loose Leaf Vaporizer |
| Medium marijuana and Very Low Nicotine Content cigarette | Experimental | Participants will vape a 50/50 mixture of medium marijuana (<5% THC) and Very Low Nicotine Content cigarette (0.42 mg/g nicotine content) Receives: Drug: Cannabis; Drug: Nicotine; Device: Pax Loose Leaf Vaporizer |
| High marijuana and regular cigarette | Experimental | Participants will vape a 50/50 mixture of high marijuana (>10% THC) and regular cigarette (25.94 mg/g nicotine content) Receives: Drug: Cannabis; Drug: Nicotine; Device: Pax Loose Leaf Vaporizer |
| High marijuana and Very Low Nicotine Content cigarette | Experimental | Participants will vape a 50/50 mixture of high marijuana (>10% THC) and Very Low Nicotine Content cigarette (0.42 mg/g nicotine content) Receives: Drug: Cannabis; Drug: Nicotine; Device: Pax Loose Leaf Vaporizer |
| High marijuana only | Experimental | Participants will vape high marijuana (>10% THC) Receives: Drug: Cannabis; Device: Pax Loose Leaf Vaporizer |
| Regular cigarette only | Experimental | Participants will vape a regular cigarette (25.94 mg/g nicotine content) Receives: Drug: Nicotine; Device: Pax Loose Leaf Vaporizer |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in peak plasma concentration of THC
To assess the differences between THC dosages, the study investigators will determine maximum plasma THC concentration (Cmax) using plasma THC concentrations from the standardized sessions.
Measured: From Baseline to Day 1
Change in peak plasma concentration of THC
To assess the differences between THC dosages, the study investigators will determine maximum plasma THC concentration (Cmax) using plasma THC concentrations from the standardized sessions.
Measured: From Day 1 to Day 2
Change in peak plasma concentration of THC
To assess the differences between THC dosages, the study investigators will determine maximum plasma THC concentration (Cmax) using plasma THC concentrations from the standardized sessions.
Measured: From Day 2 to Day 3
Change in peak plasma concentration of THC
To assess the differences between THC dosages, the study investigators will determine maximum plasma THC concentration (Cmax) using plasma THC concentrations from the standardized sessions.
Measured: From Day 3 to Day 4
Change in peak plasma concentration of THC
To assess the differences between THC dosages, the study investigators will determine maximum plasma THC concentration (Cmax) using plasma THC concentrations from the standardized sessions.
Measured: From Day 4 to Day 5
Change in peak plasma concentration of THC
To assess the differences between THC dosages, the study investigators will determine maximum plasma THC concentration (Cmax) using plasma THC concentrations from the standardized sessions.
Measured: From Day 5 to Day 6
Change in peak plasma concentration of THC
To assess the differences between THC dosages, the study investigators will determine maximum plasma THC concentration (Cmax) using plasma THC concentrations from the standardized sessions.
Measured: From Day 6 to Day 7
Change in peak plasma concentration of THC
To assess the differences between THC dosages, the study investigators will determine maximum plasma THC concentration (Cmax) using plasma THC concentrations from the standardized sessions.
Measured: From Day 7 to Day 8
Change in Peak plasma concentration of nicotine
To assess the differences between nicotine dosages, the study investigators will determine maximum plasma nicotine concentration (Cmax) using plasma nicotine concentrations from the standardized sessions.
Measured: From Baseline to Day 1
Change in Peak plasma concentration of nicotine
To assess the differences between nicotine dosages, the study investigators will determine maximum plasma nicotine concentration (Cmax) using plasma nicotine concentrations from the standardized sessions.
Measured: From Day 1 to Day 2
Change in Peak plasma concentration of nicotine
To assess the differences between nicotine dosages, the study investigators will determine maximum plasma nicotine concentration (Cmax) using plasma nicotine concentrations from the standardized sessions.
Measured: From Day 2 to Day 3
Change in Peak plasma concentration of nicotine
To assess the differences between nicotine dosages, the study investigators will determine maximum plasma nicotine concentration (Cmax) using plasma nicotine concentrations from the standardized sessions.
Measured: From Day 3 to Day 4
Change in Peak plasma concentration of nicotine
To assess the differences between nicotine dosages, the study investigators will determine maximum plasma nicotine concentration (Cmax) using plasma nicotine concentrations from the standardized sessions.
Measured: From Day 4 to Day 5
Change in Peak plasma concentration of nicotine
To assess the differences between nicotine dosages, the study investigators will determine maximum plasma nicotine concentration (Cmax) using plasma nicotine concentrations from the standardized sessions.
Measured: From Day 5 to Day 6
Change in Peak plasma concentration of nicotine
To assess the differences between nicotine dosages, the study investigators will determine maximum plasma nicotine concentration (Cmax) using plasma nicotine concentrations from the standardized sessions.
Measured: From Day 6 to Day 7
Change in Peak plasma concentration of nicotine
To assess the differences between nicotine dosages, the study investigators will determine maximum plasma nicotine concentration (Cmax) using plasma nicotine concentrations from the standardized sessions.
Measured: From Day 7 to Day 8
Secondary outcomes (24)
Cardiovascular effects among dosages using heart rate as a measure
The investigators will compare maximum change in heart rate as well as an integrated measure of heart rate over the first 180 minutes after the standardized session among dosages.
Measured: From Baseline to Day 1
Cardiovascular effects among dosages using heart rate as a measure
The investigators will compare maximum change in heart rate as well as an integrated measure of heart rate over the first 180 minutes after the standardized session among dosages.
Measured: From Day 1 to Day 2
Cardiovascular effects among dosages using heart rate as a measure
The investigators will compare maximum change in heart rate as well as an integrated measure of heart rate over the first 180 minutes after the standardized session among dosages.
Measured: From Day 2 to Day 3
Cardiovascular effects among dosages using heart rate as a measure
The investigators will compare maximum change in heart rate as well as an integrated measure of heart rate over the first 180 minutes after the standardized session among dosages.
Measured: From Day 3 to Day 4
Cardiovascular effects among dosages using heart rate as a measure
The investigators will compare maximum change in heart rate as well as an integrated measure of heart rate over the first 180 minutes after the standardized session among dosages.
Measured: From Day 4 to Day 5
Cardiovascular effects among dosages using heart rate as a measure
The investigators will compare maximum change in heart rate as well as an integrated measure of heart rate over the first 180 minutes after the standardized session among dosages.
Measured: From Day 5 to Day 6
Cardiovascular effects among dosages using heart rate as a measure
The investigators will compare maximum change in heart rate as well as an integrated measure of heart rate over the first 180 minutes after the standardized session among dosages.
Measured: From Day 6 to Day 7
Cardiovascular effects among dosages using heart rate as a measure
The investigators will compare maximum change in heart rate as well as an integrated measure of heart rate over the first 180 minutes after the standardized session among dosages.
Measured: From Day 7 to Day 8
Area under the plasma concentration versus time curve (AUC)
To assess the differences of absorption among dosages, the study investigators will determine the AUC using plasma nicotine and THC concentrations from the standardized sessions.
Measured: From Baseline to Day 1
Area under the plasma concentration versus time curve (AUC)
To assess the differences of absorption among dosages, the study investigators will determine the AUC using plasma nicotine and THC concentrations from the standardized sessions.
Measured: From Day 1 to Day 2
Area under the plasma concentration versus time curve (AUC)
To assess the differences of absorption among dosages, the study investigators will determine the AUC using plasma nicotine and THC concentrations from the standardized sessions.
Measured: From Day 2 to Day 3
Area under the plasma concentration versus time curve (AUC)
To assess the differences of absorption among dosages, the study investigators will determine the AUC using plasma nicotine and THC concentrations from the standardized sessions.
Measured: From Day 3 to Day 4
Area under the plasma concentration versus time curve (AUC)
To assess the differences of absorption among dosages, the study investigators will determine the AUC using plasma nicotine and THC concentrations from the standardized sessions.
Measured: From Day 4 to Day 5
Area under the plasma concentration versus time curve (AUC)
To assess the differences of absorption among dosages, the study investigators will determine the AUC using plasma nicotine and THC concentrations from the standardized sessions.
Measured: From Day 5 to Day 6
Area under the plasma concentration versus time curve (AUC)
To assess the differences of absorption among dosages, the study investigators will determine the AUC using plasma nicotine and THC concentrations from the standardized sessions.
Measured: From Day 6 to Day 7
Area under the plasma concentration versus time curve (AUC)
To assess the differences of absorption among dosages, the study investigators will determine the AUC using plasma nicotine and THC concentrations from the standardized sessions.
Measured: From Day 7 to Day 8
Change in subjective effects scores using the Marijuana Cravings Questionnaire (MCQ)
Self-assessed cravings will be measured using the MCQ. Questions on the MCQ are scored on a 7 point scale of 1 = Strongly Disagree and 7 = Strongly Disagree, with higher scores indicating increased cravings.
Measured: From Baseline to Day 1
Change in subjective effects scores using the Marijuana Cravings Questionnaire (MCQ)
Self-assessed cravings will be measured using the MCQ. Questions on the MCQ are scored on a 7 point scale of 1 = Strongly Disagree and 7 = Strongly Disagree, with higher scores indicating increased craving of marijuana.
Measured: From Day 1 to Day 2
Change in subjective effects scores using the Marijuana Cravings Questionnaire (MCQ)
Self-assessed cravings will be measured using the MCQ. Questions on the MCQ are scored on a 7 point scale of 1 = Strongly Disagree and 7 = Strongly Disagree, with higher scores indicating increased cravings.
Measured: From Day 2 to Day 3
Change in subjective effects scores using the Marijuana Cravings Questionnaire (MCQ)
Self-assessed cravings will be measured using the MCQ. Questions on the MCQ are scored on a 7 point scale of 1 = Strongly Disagree and 7 = Strongly Disagree, with higher scores indicating increased cravings.
Measured: From Day 3 to Day 4
Change in subjective effects scores using the Marijuana Cravings Questionnaire (MCQ)
Self-assessed cravings will be measured using the MCQ. Questions on the MCQ are scored on a 7 point scale of 1 = Strongly Disagree and 7 = Strongly Disagree, with higher scores indicating increased cravings.
Measured: From Day 4 to Day 5
Change in subjective effects scores using the Marijuana Cravings Questionnaire (MCQ)
Self-assessed cravings will be measured using the MCQ. Questions on the MCQ are scored on a 7 point scale of 1 = Strongly Disagree and 7 = Strongly Disagree, with higher scores indicating increased cravings.
Measured: From Day 5 to Day 6
Change in subjective effects scores using the Marijuana Cravings Questionnaire (MCQ)
Self-assessed cravings will be measured using the MCQ. Questions on the MCQ are scored on a 7 point scale of 1 = Strongly Disagree and 7 = Strongly Disagree, with higher scores indicating increased cravings.
Measured: From Day 6 to Day 7
Change in subjective effects scores using the Marijuana Cravings Questionnaire (MCQ)
Self-assessed cravings will be measured using the MCQ. Questions on the MCQ are scored on a 7 point scale of 1 = Strongly Disagree and 7 = Strongly Disagree, with higher scores indicating increased cravings.
Measured: From Day 7 to Day 8
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted21 Aug 2023
- Study start1 Jul 2025
- Primary completion1 Feb 2028 (estimated)
- Study completion1 Feb 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for THCStudies of the same condition, open and under way.
- More trials run by University of California, San FranciscoThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 48 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of California, San Francisco
- Sponsor type
- University, hospital or other
- Collaborators
- National Institute on Drug Abuse (NIDA), National Institutes of Health (NIH), Food and Drug Administration (FDA)
- Responsible party
- Sponsor
- Investigators
- Gideon St Helen, Principal investigator, University of California, San Francisco
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05999383
- Sponsor's protocol ID
- 23-38884
- Other IDs
- 1R01DA056451-01A1
- Acronym
- CANNIC
- Status last verified
- Jan 2026
- First submitted
- 11 Aug 2023
- Last updated
- 7 Jan 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 7 Jan 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Understanding the Clinical Pharmacology of Marijuana-Tobacco Co-administration
- ClinicalTrials.gov ID
- NCT05999383
- Acronym / sponsor ID
- CANNIC / 23-38884
- Conditions
- THC, Cannabis, Cannabis Use, Cannabis Smoking, Tobacco Use, Vaping
- Keywords
- THC, Cannabis, Marijuana, Nicotine, Vape
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 48 participants (estimated)
- Lead sponsor
- University of California, San FranciscoUniversity, hospital or other
- Collaborators
- National Institute on Drug Abuse (NIDA), National Institutes of Health (NIH), Food and Drug Administration (FDA)
- Study start
- 1 Jul 2025 (actual)
- Primary completion
- 1 Feb 2028 (estimated)
- Study completion
- 1 Feb 2028 (estimated)
- First posted
- 21 Aug 2023 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This is a crossover, randomized, double-blinded clinical pharmacology study enrolling dual cannabis-tobacco smokers to better understand the combined effects of co-administering cannabis and tobacco. The project aims to describe the pharmacokinetics and pharmacodynamics of marijuana-tobacco co-administration by delivering THC and nicotine in various combinations. This foundational study will establish a research program focused on elucidating the public health consequences of marijuana-tobacco co-use.
Detailed description
This is a single-center, within-subject (crossover), randomized, double-blinded clinical pharmacology study of over 8 study visits (days). Participants will be non-treatment-seeking, healthy frequent users of both marijuana and tobacco/nicotine, age 21 to 65 years (21 years because of California tobacco control law). Participants will be marijuana users of any race who smoke or vape marijuana or THC extracts at least three days a week for the past 3 months or more. The study investigators will use positive urine toxicology THC results and self-report of marijuana smoking/vaping to determine eligibility. Participants must also be current users of inhaled forms of tobacco/nicotine (cigarettes, cigars, e-cigarettes) who use the product daily over the past 3 months.
Each study day will consist of a standardized session of 5 puffs of one of 8 study conditions using a PAX-3 vaporizer (PAX Labs, Inc.). Blood will be sampled multiple times for plasma THC, nicotine, and catecholamines, questionnaires administered for sensory and subjective effects, and heart rate, skin blood flow, and skin temperature will be measured. After 6 hours of abstinence, participants will have 60 minutes of ad libitum access to the assigned study condition, during which heart rate and blood pressure will be continuously monitored, blood sampled before and after for THC, nicotine, and platelet aggregation measured, and questionnaires administered.
Studies will be conducted at the Clinical \& Translational Science Institute (CTSI) Clinical Research Services-supported research ward at Zuckerberg San Francisco General.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind (participant, investigator)
- Number of arms
- 8
| Arm | Type | Receives |
|---|---|---|
| Placebo marijuana and regular cigarette | Experimental | Drug: Nicotine, Device: Pax Loose Leaf Vaporizer, Other: Placebo MarijuanaParticipants will vape a 50/50 mixture of placebo marijuana (0% THC) and regular cigarette (25.94 mg/g nicotine content) |
| Placebo marijuana and Very Low Nicotine Content cigarette | Experimental | Drug: Nicotine, Device: Pax Loose Leaf Vaporizer, Other: Placebo MarijuanaParticipants will vape a 50/50 mixture of placebo marijuana (0% THC) and Very Low Nicotine Content cigarette (0.42 mg/g nicotine content) |
| Medium marijuana and regular cigarette | Experimental | Drug: Cannabis, Drug: Nicotine, Device: Pax Loose Leaf VaporizerParticipants will vape a 50/50 mixture of medium marijuana (<5% THC) and regular cigarette (25.94 mg/g nicotine content) |
| Medium marijuana and Very Low Nicotine Content cigarette | Experimental | Drug: Cannabis, Drug: Nicotine, Device: Pax Loose Leaf VaporizerParticipants will vape a 50/50 mixture of medium marijuana (<5% THC) and Very Low Nicotine Content cigarette (0.42 mg/g nicotine content) |
| High marijuana and regular cigarette | Experimental | Drug: Cannabis, Drug: Nicotine, Device: Pax Loose Leaf VaporizerParticipants will vape a 50/50 mixture of high marijuana (>10% THC) and regular cigarette (25.94 mg/g nicotine content) |
| High marijuana and Very Low Nicotine Content cigarette | Experimental | Drug: Cannabis, Drug: Nicotine, Device: Pax Loose Leaf VaporizerParticipants will vape a 50/50 mixture of high marijuana (>10% THC) and Very Low Nicotine Content cigarette (0.42 mg/g nicotine content) |
| High marijuana only | Experimental | Drug: Cannabis, Device: Pax Loose Leaf VaporizerParticipants will vape high marijuana (>10% THC) |
| Regular cigarette only | Experimental | Drug: Nicotine, Device: Pax Loose Leaf VaporizerParticipants will vape a regular cigarette (25.94 mg/g nicotine content) |
Who may qualify
- Ages
- 21 to 65 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (9 listed)
- Heart rate < 105 beats per minute (BPM)*
- Systolic Blood Pressure < 160 and > 90*
- Diastolic Blood Pressure < 100 and > 50*
- Considered out of range if both machine and manual readings are above/below these thresholds.
- Body Mass Index (BMI) ≤ 38.0 (at investigator's discretion for higher BMI if no other concurrent health issues)
Key exclusion criteria (48 listed)
- Unstable medical conditions:
- Hypertension if uncontrolled (meaning participant has a diagnosis, but they are not taking medication/under treatment (e.g., diet or exercise plan)
- Drug/Alcohol Dependence
- Psychiatric conditions
- Current regular use of any psychiatric medications with the exception of Selective serotonin reuptake inhibitors (SSRI) and serotonin-norepinephrine reuptake inhibitors (SNRI) and current evaluation by the PI that the participant is otherwise healthy, stable, and able to participate
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| CannabisAlso: MarijuanaParticipants will vape marijuana in varying doses from the PAX device | Drug | High marijuana and Very Low Nicotine Content cigarette, High marijuana and regular cigarette, High marijuana only, Medium marijuana and Very Low Nicotine Content cigarette, Medium marijuana and regular cigarette |
| NicotineAlso: Nicotine productParticipants will vape Regular and Very Low Nicotine content cigarettes from the PAX device | Drug | High marijuana and Very Low Nicotine Content cigarette, High marijuana and regular cigarette, Medium marijuana and Very Low Nicotine Content cigarette, Medium marijuana and regular cigarette, Placebo marijuana and Very Low Nicotine Content cigarette, Placebo marijuana and regular cigarette, Regular cigarette only |
| Pax Loose Leaf VaporizerAlso: Electronic vaporizorIn all arms, participants will be using the PAX Loose Leave Vaporizer. | Device | High marijuana and Very Low Nicotine Content cigarette, High marijuana and regular cigarette, High marijuana only, Medium marijuana and Very Low Nicotine Content cigarette, Medium marijuana and regular cigarette, Placebo marijuana and Very Low Nicotine Content cigarette, Placebo marijuana and regular cigarette, Regular cigarette only |
| Placebo MarijuanaAlso: Placebo for MarijuanaParticipants will vape placebo marijuana from the PAX device | Other | Placebo marijuana and Very Low Nicotine Content cigarette, Placebo marijuana and regular cigarette |
Primary outcome
Change in peak plasma concentration of THC
Time frame: From Baseline to Day 1
To assess the differences between THC dosages, the study investigators will determine maximum plasma THC concentration (Cmax) using plasma THC concentrations from the standardized sessions.
Change in peak plasma concentration of THC
Time frame: From Day 1 to Day 2
To assess the differences between THC dosages, the study investigators will determine maximum plasma THC concentration (Cmax) using plasma THC concentrations from the standardized sessions.
Change in peak plasma concentration of THC
Time frame: From Day 2 to Day 3
To assess the differences between THC dosages, the study investigators will determine maximum plasma THC concentration (Cmax) using plasma THC concentrations from the standardized sessions.
Change in peak plasma concentration of THC
Time frame: From Day 3 to Day 4
To assess the differences between THC dosages, the study investigators will determine maximum plasma THC concentration (Cmax) using plasma THC concentrations from the standardized sessions.
Change in peak plasma concentration of THC
Time frame: From Day 4 to Day 5
To assess the differences between THC dosages, the study investigators will determine maximum plasma THC concentration (Cmax) using plasma THC concentrations from the standardized sessions.
Change in peak plasma concentration of THC
Time frame: From Day 5 to Day 6
To assess the differences between THC dosages, the study investigators will determine maximum plasma THC concentration (Cmax) using plasma THC concentrations from the standardized sessions.
Change in peak plasma concentration of THC
Time frame: From Day 6 to Day 7
To assess the differences between THC dosages, the study investigators will determine maximum plasma THC concentration (Cmax) using plasma THC concentrations from the standardized sessions.
Change in peak plasma concentration of THC
Time frame: From Day 7 to Day 8
To assess the differences between THC dosages, the study investigators will determine maximum plasma THC concentration (Cmax) using plasma THC concentrations from the standardized sessions.
Change in Peak plasma concentration of nicotine
Time frame: From Baseline to Day 1
To assess the differences between nicotine dosages, the study investigators will determine maximum plasma nicotine concentration (Cmax) using plasma nicotine concentrations from the standardized sessions.
Change in Peak plasma concentration of nicotine
Time frame: From Day 1 to Day 2
To assess the differences between nicotine dosages, the study investigators will determine maximum plasma nicotine concentration (Cmax) using plasma nicotine concentrations from the standardized sessions.
Change in Peak plasma concentration of nicotine
Time frame: From Day 2 to Day 3
To assess the differences between nicotine dosages, the study investigators will determine maximum plasma nicotine concentration (Cmax) using plasma nicotine concentrations from the standardized sessions.
Change in Peak plasma concentration of nicotine
Time frame: From Day 3 to Day 4
To assess the differences between nicotine dosages, the study investigators will determine maximum plasma nicotine concentration (Cmax) using plasma nicotine concentrations from the standardized sessions.
Change in Peak plasma concentration of nicotine
Time frame: From Day 4 to Day 5
To assess the differences between nicotine dosages, the study investigators will determine maximum plasma nicotine concentration (Cmax) using plasma nicotine concentrations from the standardized sessions.
Change in Peak plasma concentration of nicotine
Time frame: From Day 5 to Day 6
To assess the differences between nicotine dosages, the study investigators will determine maximum plasma nicotine concentration (Cmax) using plasma nicotine concentrations from the standardized sessions.
Change in Peak plasma concentration of nicotine
Time frame: From Day 6 to Day 7
To assess the differences between nicotine dosages, the study investigators will determine maximum plasma nicotine concentration (Cmax) using plasma nicotine concentrations from the standardized sessions.
Change in Peak plasma concentration of nicotine
Time frame: From Day 7 to Day 8
To assess the differences between nicotine dosages, the study investigators will determine maximum plasma nicotine concentration (Cmax) using plasma nicotine concentrations from the standardized sessions.
24 secondary outcomes
Cardiovascular effects among dosages using heart rate as a measure
Time frame: From Baseline to Day 1
Cardiovascular effects among dosages using heart rate as a measure
Time frame: From Day 1 to Day 2
Cardiovascular effects among dosages using heart rate as a measure
Time frame: From Day 2 to Day 3
Cardiovascular effects among dosages using heart rate as a measure
Time frame: From Day 3 to Day 4
Cardiovascular effects among dosages using heart rate as a measure
Time frame: From Day 4 to Day 5
Cardiovascular effects among dosages using heart rate as a measure
Time frame: From Day 5 to Day 6
Cardiovascular effects among dosages using heart rate as a measure
Time frame: From Day 6 to Day 7
Cardiovascular effects among dosages using heart rate as a measure
Time frame: From Day 7 to Day 8
Area under the plasma concentration versus time curve (AUC)
Time frame: From Baseline to Day 1
Area under the plasma concentration versus time curve (AUC)
Time frame: From Day 1 to Day 2
Area under the plasma concentration versus time curve (AUC)
Time frame: From Day 2 to Day 3
Area under the plasma concentration versus time curve (AUC)
Time frame: From Day 3 to Day 4
Area under the plasma concentration versus time curve (AUC)
Time frame: From Day 4 to Day 5
Area under the plasma concentration versus time curve (AUC)
Time frame: From Day 5 to Day 6
Area under the plasma concentration versus time curve (AUC)
Time frame: From Day 6 to Day 7
Area under the plasma concentration versus time curve (AUC)
Time frame: From Day 7 to Day 8
Change in subjective effects scores using the Marijuana Cravings Questionnaire (MCQ)
Time frame: From Baseline to Day 1
Change in subjective effects scores using the Marijuana Cravings Questionnaire (MCQ)
Time frame: From Day 1 to Day 2
Change in subjective effects scores using the Marijuana Cravings Questionnaire (MCQ)
Time frame: From Day 2 to Day 3
Change in subjective effects scores using the Marijuana Cravings Questionnaire (MCQ)
Time frame: From Day 3 to Day 4
Change in subjective effects scores using the Marijuana Cravings Questionnaire (MCQ)
Time frame: From Day 4 to Day 5
Change in subjective effects scores using the Marijuana Cravings Questionnaire (MCQ)
Time frame: From Day 5 to Day 6
Change in subjective effects scores using the Marijuana Cravings Questionnaire (MCQ)
Time frame: From Day 6 to Day 7
Change in subjective effects scores using the Marijuana Cravings Questionnaire (MCQ)
Time frame: From Day 7 to Day 8
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 7 Jan 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Gideon St Helen principal investigator
University of California, San Francisco
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing Cannabis, Nicotine and Pax Loose Leaf Vaporizer in people with THC and Cannabis, run by University of California, San Francisco at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 9 inclusion and 48 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 7 Jan 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Armando Barraza (628-206-4226, armando.barraza@ucsf.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in peak plasma concentration of THC (time frame: From Baseline to Day 1). The study lists 16 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 7 Jan 2026.