NCT05999383 Understanding the Clinical Pharmacology of Marijuana-Tobacco Co-administration
| NCT ID | NCT05999383 |
| Status | Recruiting |
| Phase | Phase 2 |
| Sponsor | University of California, San Francisco |
| Condition | THC |
| Study Type | INTERVENTIONAL |
| Enrollment | 48 participants |
| Start Date | 2025-07-01 |
| Primary Completion | 2028-02-01 |
Eligibility & Interventions
Eligibility Fast-Check
Enter your details for a quick preliminary check. This does not replace medical advice.
What to Expect as a Participant
You will actively receive the study intervention — which may be a drug, biologic, device, or procedure.
In Phase 2, researchers evaluate early signs of effectiveness. You may be randomized to receive the active treatment or a comparator. Monitoring continues closely.
This trial targets 48 participants in total. It began in 2025-07-01 with a primary completion date of 2028-02-01.
⚠ This information is for research awareness only. Always consult your physician before joining any clinical trial. Participation is voluntary and you may withdraw at any time.
Brief 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. 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.
Eligibility Criteria
Inclusion Criteria: * 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 Exclusion Criteria: * 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
Contact & Investigator
Gideon St Helen
PRINCIPAL INVESTIGATOR
University of California, San Francisco
Frequently Asked Questions
Who can join the NCT05999383 clinical trial?
This trial is open to participants of all sexes, aged 21 Years or older, up to 65 Years, studying THC. Full inclusion and exclusion criteria are listed in the Eligibility Criteria section. Always confirm your eligibility with the research team before applying.
What phase is the NCT05999383 trial and what does that mean for participants?
Phase 2 trials evaluate whether the treatment shows signs of effectiveness while continuing to monitor safety. More participants are enrolled than in Phase 1 to help refine the treatment protocol.
Is NCT05999383 currently recruiting?
Yes, NCT05999383 is actively recruiting participants. Contact the research team at armando.barraza@ucsf.edu for enrollment information.
Where is the NCT05999383 trial being conducted?
This trial is being conducted at San Francisco, United States.
Who is sponsoring the NCT05999383 clinical trial?
NCT05999383 is sponsored by University of California, San Francisco. The principal investigator is Gideon St Helen at University of California, San Francisco. The trial plans to enroll 48 participants.