Alcohol + Cannabinoid Effects on DUI

(THC-ETOH-III Trial)

Overseen By Christina Luddy, BS

Age: 18 - 65

Sex: Any

Trial Phase: Phase 1

Sponsor: Yale University

Disqualifiers: Cannabis naïve, Alcohol naïve, Pregnancy, others

Compensation: Varies

Number of Visits: 1

Duration: 1 day

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial explores how alcohol and cannabinoids (compounds found in cannabis) affect driving ability and thinking skills when combined. Participants will receive different combinations of THC (the active compound in cannabis, also known as dronabinol) and alcohol to assess their effects on simulated driving tasks. The goal is to understand how these substances might impact driving safety. Individuals who have previously tried cannabis and alcohol and are between 21 and 55 years old might be suitable for this study. As a Phase 1 trial, this research focuses on understanding how these substances interact in people, offering participants a chance to contribute to groundbreaking safety insights.

Do I need to stop taking my current medications for the trial?

The trial information does not specify whether you need to stop taking your current medications.

Is there any evidence suggesting that this trial's treatments are likely to be safe?

Research has shown that both dronabinol (a type of THC) and ethanol (alcohol) have been studied separately for their effects on driving. When combined, they increase the risk of impaired driving more than when used alone, making driving more dangerous.

Dronabinol is generally safe for other uses, but it can cause side effects like drowsiness or dizziness, which might also occur here. Alcohol is well-known for affecting judgment and coordination, which is why drinking and driving is not advised.

This trial is in its early stages, with the main goal of assessing how people handle these substances together and learning more about any possible side effects. Participants will be closely monitored by the researchers to observe responses to these treatments. ^{1 2 3 4 5}

Why are researchers excited about this trial?

Researchers are excited about these treatments because they explore the combined effects of THC (from dronabinol) and ethanol on driving under the influence (DUI), a novel area of investigation. Unlike typical studies that focus on alcohol or cannabis alone, this trial looks at the interaction between both substances, which could provide new insights into impairment levels. By comparing active and placebo combinations of THC and ethanol, researchers hope to better understand their combined impact on DUI, potentially leading to more accurate assessments and interventions for impaired driving.

What evidence suggests that this trial's treatments could be effective for DUI?

This trial will compare the effects of different combinations of THC and ethanol on driving ability. Research has shown that cannabis, such as dronabinol, can affect driving ability, but the impact is often small. Participants in this trial may receive Active THC and Placebo Ethanol, Active THC and Active Ethanol, Placebo THC and Active Ethanol, or Placebo THC and Placebo Ethanol. While most drivers under the influence of marijuana experience some impairment, many can still complete road tests with only minor issues. In contrast, alcohol significantly impairs driving, contributing to over 30% of traffic deaths. Studies indicate that alcohol greatly impairs driving performance, making it very risky. Both substances affect driving, but alcohol usually causes more severe impairment than cannabis. ^{1 2 3 6 7}

Are You a Good Fit for This Trial?

This trial is for men and women aged 21 to 55 who have used alcohol and cannabis at least once. They must be able to understand and agree to the study's terms. Pregnant individuals, those with hearing issues, no prior use of cannabis or alcohol (naïve), or a sesame oil allergy cannot participate.

Inclusion Criteria

Exposed to cannabis at least once

I am between 21 and 55 years old.

Exposed to alcohol at least once

Exclusion Criteria

Cannabis naïve

Alcohol naïve

Positive pregnancy screen

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

1-2 weeks

Treatment

Participants receive ethanol clamped at BAC 0.04% and oral Dronabinol (10 mg capsule) to study effects on simulated driving and cognition

1 day

1 visit (in-person)

Follow-up

Participants are monitored for safety and effectiveness after treatment

1 week

What Are the Treatments Tested in This Trial?

Interventions

• Active Dronabinol
• Active Ethanol
• Placebo

Trial Overview The study aims to assess how active Dronabinol (a synthetic THC), ethanol (alcohol), and placebo affect simulated driving performance and related thinking skills. Participants will receive these substances in a controlled environment.

How Is the Trial Designed?

Group I: Placebo THC and Active Ethanol Experimental Treatment 2 Interventions

Group II: Active THC and Placebo Ethanol Experimental Treatment 2 Interventions

Group III: Active THC and Active Ethanol Experimental Treatment 2 Interventions

Group IV: Placebo THC and Placebo Ethanol Placebo Group 1 Intervention

Who Is Running the Clinical Trial?

Yale University

Lead Sponsor

Trials

1,963

Recruited

3,046,000+

Published Research Related to This Trial

A daily dose of 40 mg of rimonabant for 15 days effectively reduced the physiological effects of smoked cannabis, such as tachycardia, similar to a single higher dose of 90 mg on the first day of treatment.

While the 40 mg dose significantly decreased subjective effects of cannabis on day 8, it did not maintain this effect by day 15, indicating that repeated dosing may not consistently reduce the subjective experience of cannabis effects over time.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Single and multiple doses of rimonabant antagonize acute effects of smoked cannabis in male cannabis users. Huestis, MA., Boyd, SJ., Heishman, SJ., et al.[2019]

The study found that combining ethanol and marihuana significantly worsened psychomotor performance, particularly skills needed for driving, indicating an additive or synergistic effect on impairment.

Interestingly, taking ethanol before smoking marihuana did not significantly affect subjective feelings of intoxication, heart rate, or THC levels in the blood, suggesting that the combination primarily impacts performance rather than subjective experiences.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Interaction between marihuana and ethanol: effects on psychomotor performance. Perez-Reyes, M., Hicks, RE., Bumberry, J., et al.[2019]

This study will assess the effects of both oral and vaporized cannabis on driving performance, cognitive abilities, and field sobriety in healthy adults, involving 64 participants across two double-blind, placebo-controlled trials.

By examining the impact of cannabis alone and in combination with alcohol, the research aims to enhance understanding of impairment levels, which could influence public policy and law enforcement standards regarding cannabis and alcohol use.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

The effects of oral and vaporized cannabis alone, and in combination with alcohol, on driving performance using the STISIM driving simulator: A two-part, double-blind, double-dummy, placebo-controlled, randomized crossover clinical laboratory protocol. Zamarripa, CA., Novak, MD., Weerts, EM., et al.[2023]

High doses of cannabis significantly impaired driving performance more than lower doses, while alcohol had minimal effects and did not enhance impairment when combined with cannabis.

Both substances increased speed and variability in driving, but high-dose cannabis led to decreased mean speed and longer reaction times, highlighting the need for further research on their individual effects on driving safety.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

The effects of cannabis and alcohol on simulated arterial driving: Influences of driving experience and task demand. Lenné, MG., Dietze, PM., Triggs, TJ., et al.[2022]

This study is the first randomized controlled trial to evaluate the effectiveness of dronabinol, a form of Δ9-THC, in reducing opioid consumption in adults with traumatic injuries, involving 122 participants over a 48-hour treatment period.

The trial aims to determine if adding dronabinol to standard pain management can lower the amount of opioids needed, potentially offering a safer alternative for pain relief in acute injury situations.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Efficacy of Dronabinol for Acute Pain Management in Adults with Traumatic Injury: Study Protocol of A Randomized Controlled Trial. Swartwood, C., Salottolo, K., Madayag, R., et al.[2020]

Citations

1. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC2722956/

THE EFFECT OF CANNABIS COMPARED WITH ... Surprisingly, given the alarming results of cognitive studies, most marijuana-intoxicated drivers show only modest impairments on actual road tests.

2. cdc.gov cdc.gov/cannabis/health-effects/driving.html

Cannabis and Driving Driving under the influence of drugs, including cannabis, is also dangerous and illegal. Driving is a complex task that requires your full ...

3. sciencedirect.com sciencedirect.com/science/article/pii/S0379073823003043

Driving under the influence of cannabis: A 5-year ... The aim of this study was to examine the concentration of cannabinoids in blood samples of driving-under-the-influence (DUI) offenders.

4. aaafoundation.org aaafoundation.org/evaluation-data-drivers-arrested-driving-influence-relation-per-se-limits-cannabis/

An Evaluation of Data from Drivers Arrested for Driving ... This study examines the relationship between toxicological test results and performance on a battery of physiological and psychomotor measures used by law ...

5. jamanetwork.com jamanetwork.com/journals/jamapsychiatry/fullarticle/2807719

Evaluation of Field Sobriety Tests for Identifying Drivers ... Conversely, almost all individuals (92.7%) who officers believed to have received THC were identified as FST impaired, in contrast to simulator ...

6. sciencedirect.com sciencedirect.com/science/article/abs/pii/S0306460323000096

Driving under the influence of cannabis, alcohol, and illicit ... Substance use is a common contributing factor in fatal MVCs; national data indicate that alcohol, cannabis, and opioids were present in 36%, 38%, and 16% of ...

7. ncsl.org ncsl.org/transportation/drugged-driving-marijuana-impaired-driving

Brief Drugged Driving | Marijuana-Impaired Driving Under the influence DUID: Requies the driver to be under the influence of or affected by THC; Permissible inference law: Applies if THC is identified in a ...