NCT05999383

Understanding the Clinical Pharmacology of Marijuana-Tobacco Co-administration

• Status: Recruiting
• Phase: Phase 2
• Study type: Interventional
• Enrollment: 48 (estimated)
• Sponsor: University of California, San Francisco · Academic / Other
• Sex: All
• Age: 21 Years – 65 Years
• Healthy volunteers: Accepted

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.

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

Interventions

Type	Name	Description
DRUG	Cannabis	Participants will vape marijuana in varying doses from the PAX device
DRUG	Nicotine	Participants will vape Regular and Very Low Nicotine content cigarettes from the PAX device
DEVICE	Pax Loose Leaf Vaporizer	In all arms, participants will be using the PAX Loose Leave Vaporizer.
OTHER	Placebo Marijuana	Participants will vape placebo marijuana from the PAX device

Timeline

• Start date: 2025-07-01
• Primary completion: 2028-02-01
• Completion: 2028-02-01
• First posted: 2023-08-21
• Last updated: 2026-01-07

Locations

1 site across 1 country: United States

Regulatory

• FDA-regulated drug study