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Effects of Inhaled Cannabis on Driving Performance

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details.
 
ClinicalTrials.gov Identifier: NCT01620177
Recruitment Status : Completed
First Posted : June 15, 2012
Results First Posted : June 1, 2017
Last Update Posted : May 2, 2018
Sponsor:
Collaborators:
National Highway Traffic Safety Administration (NHTSA)
National Institute on Drug Abuse (NIDA)
Information provided by (Responsible Party):
Gary R Gaffney, University of Iowa

Study Type Interventional
Study Design Allocation: Randomized;   Intervention Model: Crossover Assignment;   Masking: Triple (Participant, Investigator, Outcomes Assessor);   Primary Purpose: Basic Science
Conditions Alcohol Drinking
Cannabis
Interventions Drug: Alcohol(oral) and placebo
Drug: Cannabis(THC)(Inhaled) and Placebo
Enrollment 98
Recruitment Details  
Pre-assignment Details  
Arm/Group Title Overall Study
Hide Arm/Group Description Individuals who completed the study completed all six arms of the study and the data is aggregated. Non-completers may have completed some arms and not others and their data is aggregated. There will be six study visits where the subject will arrive at the Clinical Research Unit(University of Iowa Hospitals & Clinics) the night before dosing. At each visit subjects will be receive one of the following six dosing regimens: placebo alcohol with placebo cannabis; placebo alcohol with low-dose cannabis, placebo alcohol with higher-dose of cannabis, low dose alcohol with placebo cannabis; low dose alcohol with low dose cannabis, low dose alcohol with higher-dose of cannabis.
Period Title: Overall Study
Started 98
Completed 19
Not Completed 79
Reason Not Completed
Failure at Screening Visit             43
Withdrawal by Subject             26
Lost to Follow-up             7
Physician Decision             2
Randomized, Not Active due to Scheduling             1
Arm/Group Title Overall Study
Hide Arm/Group Description Individuals who completed the study completed all six arms of the study and the data is aggregated. Non-completers may have completed some arms and not others and their data is aggregated.
Overall Number of Baseline Participants 98
Hide Baseline Analysis Population Description
There was no baseline group, but rather all subjects who completed experienced the baseline dosing condition of placebo cannabis and placebo alcohol.
Age, Categorical  
Measure Type: Count of Participants
Unit of measure:  Participants
Number Analyzed 98 participants
<=18 years
0
   0.0%
Between 18 and 65 years
98
 100.0%
>=65 years
0
   0.0%
Sex: Female, Male  
Measure Type: Count of Participants
Unit of measure:  Participants
Number Analyzed 98 participants
Female
39
  39.8%
Male
59
  60.2%
Ethnicity (NIH/OMB)  
Measure Type: Count of Participants
Unit of measure:  Participants
Number Analyzed 98 participants
Hispanic or Latino
8
   8.2%
Not Hispanic or Latino
89
  90.8%
Unknown or Not Reported
1
   1.0%
Race (NIH/OMB)  
Measure Type: Count of Participants
Unit of measure:  Participants
Number Analyzed 98 participants
American Indian or Alaska Native
0
   0.0%
Asian
1
   1.0%
Native Hawaiian or Other Pacific Islander
0
   0.0%
Black or African American
5
   5.1%
White
84
  85.7%
More than one race
6
   6.1%
Unknown or Not Reported
2
   2.0%
Region of Enrollment  
Measure Type: Number
Unit of measure:  Participants
United States Number Analyzed 98 participants
98
1.Primary Outcome
Title Driving Performance
Hide Description Measured by standard deviation of lane position. Metrics of driving performance were modeled using the SAS GLM Select function to identify changes in driver performance. Numbers represents coefficients on the regression equation such that this increase would be expected for every unit increase. A unit for THC is 1 ng/ml and a unit for BAC is 0.01% BAC. In understanding the regression coefficients, for THC the units for the coefficient would be expressed as cm per (ng/ml of THC), and for BrAC the units for the coefficient would be expressed as cm per (0.01% BrAC). The overall regression equation would be represented as SDLP = Intercept + Cthc x THC + Cbrac x BrAC. The coefficients indicate the strength of the effect on driving performance with higher coefficients indicating larger effects relative to the concentrations. Coefficients of zero indicate no effect or interactive effect.
Time Frame Through entire drive, 0.5-1.3 hr post cannabis administration.
Hide Outcome Measure Data
Hide Analysis Population Description
One subject who was an extreme outlier across driving performance measures was excluded. Due to the variability in THC and BrAC levels across subjects and conditions, a regression model was used which combined all of the data.
Arm/Group Title Cannabis - THC Alcohol - BrAC (Breath Alcohol Concentration) THC x BrAC
Hide Arm/Group Description:
Data from all dosing conditions combined to estimate the effect of THC concentrations using a regression equation.
Data from all dosing conditions combined to estimate the effect of BrACconcentrations using a regression equation.
Data from all dosing conditions combined to estimate the interactive effect of THC and BrAC concentrations using a regression equation.
Overall Number of Participants Analyzed 18 18 18
Measure Type: Number
Unit of Measure: cm
0.26 0.42 0
2.Secondary Outcome
Title THC Concentration in Plasma Sample
Hide Description Measurement of THC concentration levels in plasma over the course of each visit compared to that of the other visits.
Time Frame -0.7 hr, 0.25hr, 1.1 hr, 2 hr, 3 hr, 4.5 hr, 6 hr, 8 hr post cannabis administration
Hide Outcome Measure Data
Hide Analysis Population Description
We performed noncompartmental analyses with Phoenix WinNonLin® 6.3 for Windows (Pharsight) for maximum concentration (Cmax) of 11-OH-THC (LOQ 1 μg/L).
Arm/Group Title 0% THC With 0.065 g/dL BAC 2.5-3.5% THC With 0.065 g/dL BAC 6.0-7.5% THC and 0.065 g/dL BAC 2.5-3.5% THC With 0 g/dL BAC 6.0-7.5% THC With 0 g/dL BAC 0% THC With 0 g/dL BAC
Hide Arm/Group Description:

Alcohol(oral) and placebo: Subjects will be dosed to an approximate peak BAC of 0.065%. Subjects will be tested on the decline such that subjects will be at or above the goal BAC (0.05%) throughout the drive

Cannabis(THC)(Inhaled) and Placebo: Cannabis vapor is produced from 500 mg either placebo (0% THC), approximately 2.5-3.5% THC (low dose), or approximately 6.0-7.5% THC (high dose) bulk cannabis plant material to yield doses of approximately 0, 12.5-17.5, or 30-37.5 mg THC

Alcohol(oral) and placebo: Subjects will be dosed to an approximate peak BAC of 0.065%. Subjects will be tested on the decline such that subjects will be at or above the goal BAC (0.05%) throughout the drive

Cannabis(THC)(Inhaled) and Placebo: Cannabis vapor is produced from 500 mg either placebo (0% THC), approximately 2.5-3.5% THC (low dose), or approximately 6.0-7.5% THC (high dose) bulk cannabis plant material to yield doses of approximately 0, 12.5-17.5, or 30-37.5 mg THC

Alcohol(oral) and placebo: Subjects will be dosed to an approximate peak BAC of 0.065%. Subjects will be tested on the decline such that subjects will be at or above the goal BAC (0.05%) throughout the drive

Cannabis(THC)(Inhaled) and Placebo: Cannabis vapor is produced from 500 mg either placebo (0% THC), approximately 2.5-3.5% THC (low dose), or approximately 6.0-7.5% THC (high dose) bulk cannabis plant material to yield doses of approximately 0, 12.5-17.5, or 30-37.5 mg THC

Alcohol(oral) and placebo: Subjects will be dosed to an approximate peak BAC of 0.065%. Subjects will be tested on the decline such that subjects will be at or above the goal BAC (0.05%) throughout the drive

Cannabis(THC)(Inhaled) and Placebo: Cannabis vapor is produced from 500 mg either placebo (0% THC), approximately 2.5-3.5% THC (low dose), or approximately 6.0-7.5% THC (high dose) bulk cannabis plant material to yield doses of approximately 0, 12.5-17.5, or 30-37.5 mg THC

Alcohol(oral) and placebo: Subjects will be dosed to an approximate peak BAC of 0.065%. Subjects will be tested on the decline such that subjects will be at or above the goal BAC (0.05%) throughout the drive

Cannabis(THC)(Inhaled) and Placebo: Cannabis vapor is produced from 500 mg either placebo (0% THC), approximately 2.5-3.5% THC (low dose), or approximately 6.0-7.5% THC (high dose) bulk cannabis plant material to yield doses of approximately 0, 12.5-17.5, or 30-37.5 mg THC

Alcohol(oral) and placebo: Subjects will be dosed to an approximate peak BAC of 0.065%. Subjects will be tested on the decline such that subjects will be at or above the goal BAC (0.05%) throughout the drive

Cannabis(THC)(Inhaled) and Placebo: Cannabis vapor is produced from 500 mg either placebo (0% THC), approximately 2.5-3.5% THC (low dose), or approximately 6.0-7.5% THC (high dose) bulk cannabis plant material to yield doses of approximately 0, 12.5-17.5, or 30-37.5 mg THC

Overall Number of Participants Analyzed 19 19 19 19 19 19
Median (Full Range)
Unit of Measure: ng/ml
0
(0 to 3.2)
4.8
(1.3 to 8)
7.5
(0 to 27.3)
4.1
(0 to 13.7)
7
(1.0 to 20.3)
0
(0 to 4.3)
3.Secondary Outcome
Title THC Concentration Levels in Whole Blood
Hide Description Measurement of THC concentration levels in whole blood over the course of each visit compared to that of the other visits.
Time Frame -0.7 hr, 0.25hr, 1.1 hr, 2 hr, 3 hr, 4.5 hr, 6 hr, 8 hr post cannabis
Hide Outcome Measure Data
Hide Analysis Population Description
[Not Specified]
Arm/Group Title 0% THC With 0.065 g/dL BAC 2.5-3.5% THC With 0.065 g/dL BAC 6.0-7.5% THC and 0.065 g/dL BAC 2.5-3.5% THC With 0 g/dL BAC 6.0-7.5% THC With 0 g/dL BAC 0% THC With 0 g/dL BAC
Hide Arm/Group Description:

Alcohol(oral) and placebo: Subjects will be dosed to an approximate peak BAC of 0.065%. Subjects will be tested on the decline such that subjects will be at or above the goal BAC (0.05%) throughout the drive

Cannabis(THC)(Inhaled) and Placebo: Cannabis vapor is produced from 500 mg either placebo (0% THC), approximately 2.5-3.5% THC (low dose), or approximately 6.0-7.5% THC (high dose) bulk cannabis plant material to yield doses of approximately 0, 12.5-17.5, or 30-37.5 mg THC

Alcohol(oral) and placebo: Subjects will be dosed to an approximate peak BAC of 0.065%. Subjects will be tested on the decline such that subjects will be at or above the goal BAC (0.05%) throughout the drive

Cannabis(THC)(Inhaled) and Placebo: Cannabis vapor is produced from 500 mg either placebo (0% THC), approximately 2.5-3.5% THC (low dose), or approximately 6.0-7.5% THC (high dose) bulk cannabis plant material to yield doses of approximately 0, 12.5-17.5, or 30-37.5 mg THC

Alcohol(oral) and placebo: Subjects will be dosed to an approximate peak BAC of 0.065%. Subjects will be tested on the decline such that subjects will be at or above the goal BAC (0.05%) throughout the drive

Cannabis(THC)(Inhaled) and Placebo: Cannabis vapor is produced from 500 mg either placebo (0% THC), approximately 2.5-3.5% THC (low dose), or approximately 6.0-7.5% THC (high dose) bulk cannabis plant material to yield doses of approximately 0, 12.5-17.5, or 30-37.5 mg THC

Alcohol(oral) and placebo: Subjects will be dosed to an approximate peak BAC of 0.065%. Subjects will be tested on the decline such that subjects will be at or above the goal BAC (0.05%) throughout the drive

Cannabis(THC)(Inhaled) and Placebo: Cannabis vapor is produced from 500 mg either placebo (0% THC), approximately 2.5-3.5% THC (low dose), or approximately 6.0-7.5% THC (high dose) bulk cannabis plant material to yield doses of approximately 0, 12.5-17.5, or 30-37.5 mg THC

Alcohol(oral) and placebo: Subjects will be dosed to an approximate peak BAC of 0.065%. Subjects will be tested on the decline such that subjects will be at or above the goal BAC (0.05%) throughout the drive

Cannabis(THC)(Inhaled) and Placebo: Cannabis vapor is produced from 500 mg either placebo (0% THC), approximately 2.5-3.5% THC (low dose), or approximately 6.0-7.5% THC (high dose) bulk cannabis plant material to yield doses of approximately 0, 12.5-17.5, or 30-37.5 mg THC

Alcohol(oral) and placebo: Subjects will be dosed to an approximate peak BAC of 0.065%. Subjects will be tested on the decline such that subjects will be at or above the goal BAC (0.05%) throughout the drive

Cannabis(THC)(Inhaled) and Placebo: Cannabis vapor is produced from 500 mg either placebo (0% THC), approximately 2.5-3.5% THC (low dose), or approximately 6.0-7.5% THC (high dose) bulk cannabis plant material to yield doses of approximately 0, 12.5-17.5, or 30-37.5 mg THC

Overall Number of Participants Analyzed 19 19 19 19 19 19
Median (Full Range)
Unit of Measure: ng/ml
0
(0 to 2.4)
3.7
(1.4 to 6.0)
6.0
(0 to 24.8)
2.8
(0 to 9.1)
5.0
(0 to 14.2)
0
(0 to 2.5)
Time Frame [Not Specified]
Adverse Event Reporting Description Adverse events were reported for all subjects who completed at least one dosing visit. The number of subjects varies across conditions based on the number of dosing visits by subjects who did not complete the study and which randomization arm they were assigned.
 
Arm/Group Title 0% THC With 0.065 g/dL BAC 2.5-3.5% THC With 0.065 g/dL BAC 6.0-7.5% THC and 0.065 g/dL BAC 2.5-3.5% THC With 0 g/dL BAC 6.0-7.5% THC With 0 g/dL BAC 0% THC With 0 g/dL BAC
Hide Arm/Group Description

Alcohol(oral) and placebo: Subjects will be dosed to an approximate peak BAC of 0.065%. Subjects will be tested on the decline such that subjects will be at or above the goal BAC (0.05%) throughout the drive

Cannabis(THC)(Inhaled) and Placebo: Cannabis vapor is produced from 500 mg either placebo (0% THC), approximately 2.5-3.5% THC (low dose), or approximately 6.0-7.5% THC (high dose) bulk cannabis plant material to yield doses of approximately 0, 12.5-17.5, or 30-37.5 mg THC

Alcohol(oral) and placebo: Subjects will be dosed to an approximate peak BAC of 0.065%. Subjects will be tested on the decline such that subjects will be at or above the goal BAC (0.05%) throughout the drive

Cannabis(THC)(Inhaled) and Placebo: Cannabis vapor is produced from 500 mg either placebo (0% THC), approximately 2.5-3.5% THC (low dose), or approximately 6.0-7.5% THC (high dose) bulk cannabis plant material to yield doses of approximately 0, 12.5-17.5, or 30-37.5 mg THC

Alcohol(oral) and placebo: Subjects will be dosed to an approximate peak BAC of 0.065%. Subjects will be tested on the decline such that subjects will be at or above the goal BAC (0.05%) throughout the drive

Cannabis(THC)(Inhaled) and Placebo: Cannabis vapor is produced from 500 mg either placebo (0% THC), approximately 2.5-3.5% THC (low dose), or approximately 6.0-7.5% THC (high dose) bulk cannabis plant material to yield doses of approximately 0, 12.5-17.5, or 30-37.5 mg THC

Alcohol(oral) and placebo: Subjects will be dosed to an approximate peak BAC of 0.065%. Subjects will be tested on the decline such that subjects will be at or above the goal BAC (0.05%) throughout the drive

Cannabis(THC)(Inhaled) and Placebo: Cannabis vapor is produced from 500 mg either placebo (0% THC), approximately 2.5-3.5% THC (low dose), or approximately 6.0-7.5% THC (high dose) bulk cannabis plant material to yield doses of approximately 0, 12.5-17.5, or 30-37.5 mg THC

Alcohol(oral) and placebo: Subjects will be dosed to an approximate peak BAC of 0.065%. Subjects will be tested on the decline such that subjects will be at or above the goal BAC (0.05%) throughout the drive

Cannabis(THC)(Inhaled) and Placebo: Cannabis vapor is produced from 500 mg either placebo (0% THC), approximately 2.5-3.5% THC (low dose), or approximately 6.0-7.5% THC (high dose) bulk cannabis plant material to yield doses of approximately 0, 12.5-17.5, or 30-37.5 mg THC

Alcohol(oral) and placebo: Subjects will be dosed to an approximate peak BAC of 0.065%. Subjects will be tested on the decline such that subjects will be at or above the goal BAC (0.05%) throughout the drive

Cannabis(THC)(Inhaled) and Placebo: Cannabis vapor is produced from 500 mg either placebo (0% THC), approximately 2.5-3.5% THC (low dose), or approximately 6.0-7.5% THC (high dose) bulk cannabis plant material to yield doses of approximately 0, 12.5-17.5, or 30-37.5 mg THC

All-Cause Mortality
0% THC With 0.065 g/dL BAC 2.5-3.5% THC With 0.065 g/dL BAC 6.0-7.5% THC and 0.065 g/dL BAC 2.5-3.5% THC With 0 g/dL BAC 6.0-7.5% THC With 0 g/dL BAC 0% THC With 0 g/dL BAC
Affected / at Risk (%) Affected / at Risk (%) Affected / at Risk (%) Affected / at Risk (%) Affected / at Risk (%) Affected / at Risk (%)
Total   --/--      --/--      --/--      --/--      --/--      --/--    
Hide Serious Adverse Events
0% THC With 0.065 g/dL BAC 2.5-3.5% THC With 0.065 g/dL BAC 6.0-7.5% THC and 0.065 g/dL BAC 2.5-3.5% THC With 0 g/dL BAC 6.0-7.5% THC With 0 g/dL BAC 0% THC With 0 g/dL BAC
Affected / at Risk (%) # Events Affected / at Risk (%) # Events Affected / at Risk (%) # Events Affected / at Risk (%) # Events Affected / at Risk (%) # Events Affected / at Risk (%) # Events
Total   0/29 (0.00%)      0/27 (0.00%)      0/24 (0.00%)      0/26 (0.00%)      0/31 (0.00%)      0/27 (0.00%)    
Hide Other (Not Including Serious) Adverse Events
Frequency Threshold for Reporting Other Adverse Events 0%
0% THC With 0.065 g/dL BAC 2.5-3.5% THC With 0.065 g/dL BAC 6.0-7.5% THC and 0.065 g/dL BAC 2.5-3.5% THC With 0 g/dL BAC 6.0-7.5% THC With 0 g/dL BAC 0% THC With 0 g/dL BAC
Affected / at Risk (%) # Events Affected / at Risk (%) # Events Affected / at Risk (%) # Events Affected / at Risk (%) # Events Affected / at Risk (%) # Events Affected / at Risk (%) # Events
Total   4/29 (13.79%)      4/27 (14.81%)      6/24 (25.00%)      0/26 (0.00%)      3/31 (9.68%)      0/27 (0.00%)    
Gastrointestinal disorders             
Vomiting * 1  3/29 (10.34%)  3 0/27 (0.00%)  0 4/24 (16.67%)  4 0/26 (0.00%)  0 1/31 (3.23%)  1 0/27 (0.00%)  0
Nausea * 2  0/29 (0.00%)  0 1/27 (3.70%)  1 3/24 (12.50%)  3 0/26 (0.00%)  0 0/31 (0.00%)  0 0/27 (0.00%)  0
Tooth Ache * 3 [1]  1/29 (3.45%)  1 0/27 (0.00%)  0 0/24 (0.00%)  0 0/26 (0.00%)  0 0/31 (0.00%)  0 0/27 (0.00%)  0
Nervous system disorders             
Loss of Consciousness * 4  0/29 (0.00%)  0 1/27 (3.70%)  1 0/24 (0.00%)  0 0/26 (0.00%)  0 0/31 (0.00%)  0 0/27 (0.00%)  0
Loss of Consciousness with IV Insertion * 5  0/29 (0.00%)  0 0/27 (0.00%)  0 0/24 (0.00%)  0 0/26 (0.00%)  0 1/31 (3.23%)  1 0/27 (0.00%)  0
Disorientation * 6  0/29 (0.00%)  0 0/27 (0.00%)  0 0/24 (0.00%)  0 0/26 (0.00%)  0 1/31 (3.23%)  1 0/27 (0.00%)  0
Dizziness * 7  0/29 (0.00%)  0 2/27 (7.41%)  2 2/24 (8.33%)  2 0/26 (0.00%)  0 1/31 (3.23%)  1 0/27 (0.00%)  0
Light-Headed * 8  0/29 (0.00%)  0 2/27 (7.41%)  2 0/24 (0.00%)  0 0/26 (0.00%)  0 0/31 (0.00%)  0 0/27 (0.00%)  0
Anxiety * 9  0/29 (0.00%)  0 1/27 (3.70%)  1 4/24 (16.67%)  4 0/26 (0.00%)  0 0/31 (0.00%)  0 0/27 (0.00%)  0
Headache * 10  0/29 (0.00%)  0 0/27 (0.00%)  0 0/24 (0.00%)  0 0/26 (0.00%)  0 0/31 (0.00%)  0 0/27 (0.00%)  0
Change in Status Perception * 11  0/29 (0.00%)  0 1/27 (3.70%)  1 1/24 (4.17%)  1 0/26 (0.00%)  0 0/31 (0.00%)  0 0/27 (0.00%)  0
Diaphoresis * 12  0/29 (0.00%)  0 1/27 (3.70%)  1 0/24 (0.00%)  0 0/26 (0.00%)  0 0/31 (0.00%)  0 0/27 (0.00%)  0
Renal and urinary disorders             
Incontinence * 13  0/29 (0.00%)  0 1/27 (3.70%)  1 0/24 (0.00%)  0 0/26 (0.00%)  0 0/31 (0.00%)  0 0/27 (0.00%)  0
*
Indicates events were collected by non-systematic assessment
1
Term from vocabulary, Vomiting
2
Term from vocabulary, Nausea
3
Term from vocabulary, Tooth Ache
4
Term from vocabulary, LossofConsciousness
5
Term from vocabulary, LoC with IV
6
Term from vocabulary, Disorientation
7
Term from vocabulary, Dizziness
8
Term from vocabulary, Light-Headed
9
Term from vocabulary, Anxiety
10
Term from vocabulary, Headache
11
Term from vocabulary, Status Perception
12
Term from vocabulary, Diaphoresis
13
Term from vocabulary, Incontinence
[1]
This AE was the result of wisdom teeth pain, and the participant subsequently had the teeth removed.
This study examined only occasional users and the generalization to new or frequent cannabis users is unclear.
Certain Agreements
Principal Investigators are NOT employed by the organization sponsoring the study.
There IS an agreement between Principal Investigators and the Sponsor (or its agents) that restricts the PI's rights to discuss or publish trial results after the trial is completed.
Results Point of Contact
Layout table for Results Point of Contact information
Name/Title: Dr. Timothy L. Brown, Co-PI
Organization: National Advanced Driving Simulator
Phone: 319-335-4785
EMail: timothy-l-brown@uiowa.edu
Layout table for additonal information
Responsible Party: Gary R Gaffney, University of Iowa
ClinicalTrials.gov Identifier: NCT01620177    
Other Study ID Numbers: 201109850
First Submitted: June 4, 2012
First Posted: June 15, 2012
Results First Submitted: April 17, 2017
Results First Posted: June 1, 2017
Last Update Posted: May 2, 2018