What this study is
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.
What's being tested
- Cannabis
Intervention · DRUG
Participants will vape marijuana in varying doses from the PAX device
- Nicotine
Intervention · DRUG
Participants will vape Regular and Very Low Nicotine content cigarettes from the PAX device
- Pax Loose Leaf Vaporizer
Intervention · DEVICE
In all arms, participants will be using the PAX Loose Leave Vaporizer.
- Placebo Marijuana
Intervention · OTHER
Participants will vape placebo marijuana from the PAX device
Study details
- Sponsor
- University of California, San Francisco
- Conditions
- THC · Cannabis · Cannabis Use · Cannabis Smoking · Tobacco Use · Vaping
- Enrolling
- 48 people
- Starts
- 2025-07-01
- Est. completion
- 2028-02-01
- Design
- Double-blind, randomized, crossover, Phase 2
- Record
- View on ClinicalTrials.gov ↗
Who can join
Age 21 Years – 65 YearsSex ALLHealthy volunteers AcceptedYou may qualify if
- 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
- 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
You can't join if
- Unstable medical conditions:; Heart disease; Seizures; Cancer; Thyroid disease (okay if controlled with medication); Diabetes; 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
Sign in and we'll check these against your records.Full criteria on ClinicalTrials.gov ↗
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Study locations (1)
1 openZuckerberg San Francisco General Hospital
San Francisco, California, United States
- Lisa Lawrence · ContactLisa.Lawrence@ucsf.edu
- Gideon St. Helen, PhD · Principal investigator
Recruiting
Study team
Sponsor
University of California, San Francisco
Study ID 23-38884
Principal investigator
Gideon St Helen
University of California, San Francisco
Frequently asked questions
The sponsor hasn't published answers to common questions for this trial.