THC Crossover Study

Not Applicable

Completed

• Conditions: Cannabis Smoking; Cigarette Smoking; Cardiovascular Risk Factor; Cannabis Use, Unspecified; Tobacco Use; Cannabis; Nicotine Dependence; THC; Nicotine Withdrawal
• Interventions: Other: Smoked Cannabis; Other: Vaped Cannabis; Other: Tobacco Cigarette

• Registration Number: NCT04429568
• Lead Sponsor: University of California, San Francisco

Brief Summary

This is a randomized, crossover study enrolling experienced dual cannabis-tobacco smokers (N=18) to describe the differences in THC and toxicant exposure, examining pharmacokinetic, subjective, and cardiovascular effects from smoking and vaping dry herb cannabis. This study will also examine the differences in toxicant exposure and cardiovascular disease risk between smoking cannabis and smoking tobacco cigarettes.

Detailed Description

Experienced dual cannabis-tobacco smokers will participate in a within-subject crossover study with three blocks: smoked cannabis (purchased by participants from a local dispensary), dry herb cannabis vaporizer, and usual brand tobacco cigarette. Each block will consist of 2 consecutive days on an inpatient research ward. The first inpatient day of each block will comprise of two sessions: (1) The first session will be a standardized bout to compare pharmacokinetic, physiologic, and subjective effects of cannabis and tobacco use; (2) after 6 hours of abstinence, the second session will be ad libitum access to the assigned product for 2 hours to compare subjective effects (reward, satisfaction, craving reduction) and use patterns. The second inpatient day will consist of ad libitum use of the assigned product from 8:00 in the morning to midnight. An abstinence day will be added after the second day of the last block to assess exposure and effects biomarkers during a period of abstinence from cannabis (smoked/vaped) or tobacco.

Study Timeline

• Study First Submitted: 2019-08-20
• Study First Submitted QC: 2020-06-09
• Study First Posted: 2020-06-12
• Study Start: 2020-10-30
• Status Verified: 2024-06
• Primary Completion: 2024-06-25
• Study Completion: 2024-06-25
• Last Update Submitted: 2024-06-27
• Last Update Posted: 2024-07-01

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 14

Inclusion Criteria

• Healthy on the basis of medical history and limited physical examination, as described below:

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.

• Current regular user of cannabis who smokes cannabis as joint or blunt at least 3 times a week for past 3 months
• History of cannabis vaporizer use or willingness to use the vaporizer in the study
• Current tobacco cigarette use who smokes ≥ 5 cigarettes per day
• Saliva cotinine ≥ 50 ng/ml
• Test positive for D-9-tetrahydrocannabinol (THC) at screening and self-report of cannabis use

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Exclusion Criteria

• Unstable medical conditions:

Heart disease; Uncontrolled hypertension; Thyroid disease (okay if controlled with medication); Diabetes; Hepatitis B or C or Liver disease; Glaucoma; Prostatic hypertrophy

• Psychiatric conditions:

Current or past schizophrenia, and/or current or past bipolar disorder; Adult onset attention deficit hyperactivity disorder (ADHD); Participants with current or past depression and/or anxiety disorders will be reviewed by the study physician and considered for inclusion; History of psychiatric hospitalizations are not exclusionary, but study participation will be determined as per study physician's approval

• Concurrent regular use of smokeless tobacco or pipes [occasional users of these products may be enrolled if they agree to abstain from their use during the period of the study]
• 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; Psychiatric medications: 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 study physician that the participant is otherwise healthy, stable, and able to participate.

• Other/Misc. Chronic Health Conditions:

Oral thrush; Fainting; Untreated thyroid disease; Other "life threatening illnesses" as per study physician's discretion

• Pregnancy:

Pregnancy (self-reported and urine pregnancy test); Breastfeeding (determined by self-report)

• Drug/Alcohol Dependence:

Alcohol or illicit drug dependence within the past 12 months with the exception of those who have recently completed an alcohol/drug treatment program; Positive toxicology test at the screening visit (THC & prescribed medications okay); Methadone replacement therapy

• Concurrent participation in another clinical trial
• Inability to communicate in English
• History of marijuana-induced psychosis or paranoia after smoking marijuana
• Scoring a 2 or higher on the Severity of Dependence Scale for cannabis use
• Planning to quit smoking or vaping within the next 60 days

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Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
Either of the 2 remaining products	Vaped Cannabis	* Abstinence from any product night before hospital admission * Standardized Session of assigned product: smoked cannabis, vaped cannabis, or tobacco cigarette * 6-hr abstinence and blood draws (PK) * 2 hr Free use session w/ video monitoring * Free use of assigned product * 12-hr CV monitoring * Circadian blood draws * 12-hr urine collection
Smoked Cannabis, Vaped Cannabis, or Tobacco Cigarette	Smoked Cannabis	* Abstinence from any product night before hospital admission * Standardized Session of assigned product: smoked cannabis, vaped cannabis, or tobacco cigarette * 6-hr abstinence and blood draws (PK) * 2 hr Free use session w/ video monitoring * Free use of assigned product * 12-hr cardiovascular (CV) monitoring * Circadian blood draws * 12-hr urine collection
Either of the 2 remaining products	Smoked Cannabis	* Abstinence from any product night before hospital admission * Standardized Session of assigned product: smoked cannabis, vaped cannabis, or tobacco cigarette * 6-hr abstinence and blood draws (PK) * 2 hr Free use session w/ video monitoring * Free use of assigned product * 12-hr CV monitoring * Circadian blood draws * 12-hr urine collection
Smoked Cannabis, Vaped Cannabis, or Tobacco Cigarette	Tobacco Cigarette	* Abstinence from any product night before hospital admission * Standardized Session of assigned product: smoked cannabis, vaped cannabis, or tobacco cigarette * 6-hr abstinence and blood draws (PK) * 2 hr Free use session w/ video monitoring * Free use of assigned product * 12-hr cardiovascular (CV) monitoring * Circadian blood draws * 12-hr urine collection
Smoked Cannabis, Vaped Cannabis, or Tobacco Cigarette	Vaped Cannabis	* Abstinence from any product night before hospital admission * Standardized Session of assigned product: smoked cannabis, vaped cannabis, or tobacco cigarette * 6-hr abstinence and blood draws (PK) * 2 hr Free use session w/ video monitoring * Free use of assigned product * 12-hr cardiovascular (CV) monitoring * Circadian blood draws * 12-hr urine collection
Either of the 2 remaining products	Tobacco Cigarette	* Abstinence from any product night before hospital admission * Standardized Session of assigned product: smoked cannabis, vaped cannabis, or tobacco cigarette * 6-hr abstinence and blood draws (PK) * 2 hr Free use session w/ video monitoring * Free use of assigned product * 12-hr CV monitoring * Circadian blood draws * 12-hr urine collection
Remaining product	Smoked Cannabis	* Abstinence from any product night before hospital admission * Standardized Session of assigned product: smoked cannabis, vaped cannabis, or tobacco cigarette * 6-hr abstinence and blood draws (PK) * 2 hr Free use session w/ video monitoring * Free use of assigned product * 12-hr CV monitoring * Circadian blood draws * 12-hr urine collection
Remaining product	Vaped Cannabis	* Abstinence from any product night before hospital admission * Standardized Session of assigned product: smoked cannabis, vaped cannabis, or tobacco cigarette * 6-hr abstinence and blood draws (PK) * 2 hr Free use session w/ video monitoring * Free use of assigned product * 12-hr CV monitoring * Circadian blood draws * 12-hr urine collection
Remaining product	Tobacco Cigarette	* Abstinence from any product night before hospital admission * Standardized Session of assigned product: smoked cannabis, vaped cannabis, or tobacco cigarette * 6-hr abstinence and blood draws (PK) * 2 hr Free use session w/ video monitoring * Free use of assigned product * 12-hr CV monitoring * Circadian blood draws * 12-hr urine collection

Primary Outcome Measures

Name	Time	Method
Peak plasma concentration	Day 1 of each arm	To assess the differences between smoked and vaped cannabis, we will determine maximum plasma THC concentration (Cmax) using plasma THC concentrations from the standardized sessions.
Time to peak plasma concentration	Day 1 of each arm	To assess the differences of these variables between smoked and vaped cannabis, we will determine the time to max concentration (Tmax) using plasma THC concentrations from the standardized sessions.
Subjective effects between cannabis products using the Drug Effects Questionnaire	Days 1-2 of each arm	We will assess measures from the Drug Effects Questionnaire (DEQ) and compare them between smoked and vaped cannabis.
Cardiovascular effects between cannabis products using epinephrine as a measure	Day 2 of each cannabis arm	Urine catecholamine excretion, particularly epinephrine, will be examined in 12-hour urines and compared between smoked and vaped cannabis.
Area under the plasma concentration versus time curve (AUC)	Day 1 of each arm	To assess the differences of these variables between smoked and vaped cannabis, we will determine the AUC using plasma THC concentrations from the standardized sessions.
Subjective effects between cannabis products using the Marijuana Cravings Questionnaire	Days 1-2 of each arm	We will assess measures from the Marijuana Cravings Questionnaire (MCQ) and compare them between smoked and vaped cannabis.
Subjective effects between cannabis products using the Visual Analog Scale	Days 1-2 of each arm	We will assess measures from the Visual Analog Scale (VAS) and compare them between smoked and vaped cannabis.
Max change of expired carbon monoxide	Days 1-2 of the cannabis arms	We will examine differences in max change of expired carbon monoxide (CO) from day 1 between smoked and vaped cannabis.
Exposure to toxicants between cannabis products	Days 1-2 of the cannabis arms	We will also examine how measures of use (number of puss, amount use, number of use episodes) correlate with biomarker concentrations between smoked and vaped cannabis.
Cardiovascular effects between cannabis products using platelet activation as a measure	Day 2 of each cannabis arm	We will examine differences in blood and urine biomarkers of platelet activation between smoked and vaped cannabis.
Cardiovascular effects between cannabis products using endothelial dysfunction as a measure	Day 2 of each cannabis arm	We will examine differences in blood and urine biomarkers of endothelial dysfunction and inflammation between smoked and vaped cannabis.
Differences in metabolites of volatile organic compounds (VOCs)	Days 1-2 of the cannabis arms	We will examine differences in 12-hour urine mercapturic acid metabolites of volatile organic compounds (from day 2) between smoked and vaped cannabis.
Area under the expired carbon monoxide (CO) curve (AUC)	Days 1-2 of the cannabis arms	We will examine differences in integrated AUC of expired carbon monoxide from day 1 between smoked and vaped cannabis.
Cardiovascular effects between cannabis products using heart rate as a measure	Day 1 of each arm	We will compare maximum change in heart rate as well as an integrated measure of heart rate over the first 30 minutes after the standardized session (day 1) between smoked and vaped cannabis.
Cardiovascular effects between cannabis products using oxidant stress as a measure	Day 2 of each cannabis arm	We will examine differences in blood and urine biomarkers of oxidant stress between smoked and vaped cannabis.

Secondary Outcome Measures

Name	Time	Method
Toxicant exposure between smoked tobacco and cannabis using expired carbon monoxide as the measure	Day 1 of each arm	We will examine differences in expired carbon monoxide (CO) from day 1 (both max change and integrated AUC of expired CO) between smoked tobacco and cannabis.
Toxicant exposure between smoked tobacco and cannabis using mercapturic acid as the measure	Day 2 of each arm	We will examine differences in 12-hour urine mercapturic acid metabolites of volatile organic compounds (VOCs) (from day 2) between smoked tobacco and cannabis.
Cardiovascular effects between smoked tobacco and cannabis using platelet activation as a measure	Day 2 of each arm	We will examine differences in blood and urine biomarkers of platelet activation between smoked tobacco and cannabis.
Toxicant exposure between smoked tobacco and cannabis using use as a measure	Days 1-2 of each arm	We will also examine how measures of use (number of puffs, amount use, number of use episodes) correlate with biomarker concentrations between smoked tobacco and cannabis.
Puffing behaviors across all products	Days 1-2 of each arm	We will examine how puffing behaviors are different between all products (smoked and vaped cannabis, as well as with smoked tobacco cigarettes) and how they correlate with toxicant biomarker concentrations. Vaping topography measures will be obtained from frame by frame analysis of high definition videos.
Cardiovascular effects between smoked tobacco and cannabis using heart rate as a measure	Day 1 of each arm	We will compare maximum change in heart rate as well as an integrated measure of heart rate over the first 30 minutes after the standardized session (day 1) between smoked tobacco and cannabis.
Cardiovascular effects between smoked tobacco and cannabis using epinephrine as a measure	Day 2 of each arm	Urine catecholamine excretion, particularly epinephrine, will be examined in 12-hour urines.
Cardiovascular effects between smoked tobacco and cannabis using oxidant stress as a measure	Day 2 of each arm	We will examine differences in blood and urine biomarkers of oxidant stress between smoked tobacco and cannabis.
Cardiovascular effects between smoked tobacco and cannabis using endothelial dysfunction as a measure	Day 2 of each arm	We will examine differences in blood and urine biomarkers of endothelial dysfunction and inflammation between smoked tobacco and cannabis.

Trial Locations

Locations (2)

Zuckerberg San Francisco General Hospital; 🇺🇸 San Francisco, California, United States

University of California, San Francisco; 🇺🇸 San Francisco, California, United States