RecruitingPhase 2NCT05999383

Understanding the Clinical Pharmacology of Marijuana-Tobacco Co-administration

Sponsor

University of California, San Francisco

Enrollment

48 participants

Start Date

Jul 1, 2025

Study Type

INTERVENTIONAL

Conditions

Vaping Cannabis Use Cannabis Smoking Cannabis Tobacco Use THC

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

Min Age: 21 YearsMax Age: 65 Years

Inclusion Criteria9

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 Criteria48

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