INTERVENTIONALCOMPLETEDNCT01620177

Effects of Inhaled Cannabis on Driving Performance

The purpose of this study is to expand understanding of the effects of cannabis on driving performance with and without the presence of low levels of alcohol. This project will involve the development a of a protocol and driving environment that is sensitive to the effects of cannabis on driving performance by building on prior driving situations used previously for testing the effects of alcohol on driving.

Locally preserved from ClinicalTrials.govOpen ClinicalTrials.govlast source update 2018-05-02

What this record can show

Registry results are available

Results are reported by the registry submitter and preserved exactly. They are not independent verification or a treatment recommendation.

Registry facts

Study at a glance

Phase: NA
Enrollment: 98 (ACTUAL)
Start date: 2012-07
Sponsor: Gary R Gaffney
Design: RANDOMIZED · CROSSOVER · BASIC SCIENCE
Locations: 1
Results record: Present in registry snapshot

Individuals will be recruited who are currently users of cannabis and alcohol to participate in this study. They will undergo a physical exam at screening. 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. After dosing, participants will have provide saliva samples and blood drawn periodically to check cannabis levels and will complete a driving simulation. After completing the drive, additional saliva samples and blood draws will occur and participants will be monitored until it is safe to transport home.

Linked local records

Related local records

Local links use governed condition terms or exact source-reported intervention names. They are navigation candidates, not efficacy claims.

Conditions

No published condition report matched.

Cannabinoids and active compounds

Delta(9)-tetrahydrocannabinol Ethanol

Medicines

No exact medicine-name link was found.

Interventions

What was registered

DRUG

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

Ethanol · Ethyl Alcohol

DRUG

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

Marihuana · Marijuana

Source-reported results

Results posted to the registry

3 outcomes

Results are reported by the registry submitter and preserved exactly. They are not independent verification or a treatment recommendation.

Primary outcomes: 1
Secondary outcomes: 2
Statistical analyses: 0
Adverse-event terms: 13

PRIMARYDriving Performance

Time frame: Through entire drive, 0.5-1.3 hr post cannabis administration.
Measure: NUMBER · cm
Reporting status: POSTED

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.

Population: 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.

Group	N	Value	Spread / interval
Cannabis - THC	18	0.26	-
Alcohol - BrAC (Breath Alcohol Concentration)	18	0.42	-
THC x BrAC	18	0	-

SECONDARYTHC Concentration in Plasma Sample

Eligibility

Population and criteria

Sex: ALL
Minimum age: 21 Years
Maximum age: 55 Years
Healthy volunteers: Accepted

Inclusion criteria

Healthy adult (age 21-55) men and women, based on medical and psychological evaluation
Currently valid unrestricted (except for vision correction) US driver's license
Licensed driver for at least the past two years
Drove at least 1300 miles in the past year, by self-report
Live within an 80 mile radius of NADS
Available for an overnight stay followed by a full-day study session for six sessions
Must be considered a light or moderate drinker according to Quantity-Frequency-Variability Scale (QFV)
Cannabis use with a minimum frequency averaging at least one day per quarter and no more than three days a week during the three months prior to study entry
Peripheral veins suitable for repeated venipuncture and/or placement of an intravenous catheter
Systolic blood pressure within a clinically normal range (120 ± 30 mmHg) and -diastolic blood pressure of 80 ± 20 mmHg..
Good command of written and spoken English
Female subjects with reproductive potential must agree to use (and/or have their partner use) one (1) acceptable method of birth control beginning at the screening visit throughout the study (including intervals between treatment periods/panels) and until 2 weeks after the last dose of study drug in the last treatment period. Acceptable methods of birth control include the following: intrauterine device (IUD-with or without local hormone release), diaphragm, spermicides, cervical cap, contraceptive sponge, oral contraceptives or condoms. Abstinence is an alternative lifestyle and subjects practicing abstinence may be included in the study.

Exclusion criteria

Presence of any clinically significant illness, as detected by history, physical examination, and/or laboratory tests, that might influence driving performance (e.g., seizures, sleep apnea, narcolepsy, vertigo, chronic fatigue syndrome) or put the subject at increased risk of adverse events (e.g., cardiac arrhythmia, hypertension)
History of a clinically significant adverse event associated with cannabis or alcohol intoxication
Donation of more than 450 mL of blood within 14 days of study drug administration

primary outcomes

primary measures

Driving Performance

Time frame: Through entire drive, 0.5-1.3 hr post cannabis administration.

secondary outcomes

secondary measures

THC Concentration in Plasma Sample

Time frame: -0.7 hr, 0.25hr, 1.1 hr, 2 hr, 3 hr, 4.5 hr, 6 hr, 8 hr post cannabis administration

Measurement of THC concentration levels in plasma over the course of each visit compared to that of the other visits.

THC Concentration Levels in Whole Blood

Time frame: -0.7 hr, 0.25hr, 1.1 hr, 2 hr, 3 hr, 4.5 hr, 6 hr, 8 hr post cannabis

Measurement of THC concentration levels in whole blood over the course of each visit compared to that of the other visits.

Publications

Locally readable linked articles

No exact PMID-linked public article is currently readable locally.

Snapshot provenance

Snapshot: 9b8a3c60-15bb-4387-b573-5e65c90a2a7c
Retrieved: 11/09/2026, 14:54:21
SHA-256: 2a00bba8e2d3714be156f6599061f0f435f2155dfbf6cf25545f15aec9224f1c

Group	N	Value	Spread / interval
0% THC With 0.065 g/dL BAC	19	0	0 to 3.2
2.5-3.5% THC With 0.065 g/dL BAC	19	4.8	1.3 to 8
6.0-7.5% THC and 0.065 g/dL BAC	19	7.5	0 to 27.3
2.5-3.5% THC With 0 g/dL BAC	19	4.1	0 to 13.7
6.0-7.5% THC With 0 g/dL BAC	19	7	1.0 to 20.3
0% THC With 0 g/dL BAC	19	0	0 to 4.3

Group	N	Value	Spread / interval
0% THC With 0.065 g/dL BAC	19	0	0 to 2.4
2.5-3.5% THC With 0.065 g/dL BAC	19	3.7	1.4 to 6.0
6.0-7.5% THC and 0.065 g/dL BAC	19	6.0	0 to 24.8
2.5-3.5% THC With 0 g/dL BAC	19	2.8	0 to 9.1
6.0-7.5% THC With 0 g/dL BAC	19	5.0	0 to 14.2
0% THC With 0 g/dL BAC	19	0	0 to 2.5

Milestone	Overall Study
STARTED	98
COMPLETED	19
NOT COMPLETED	79

Event	System	Groups: affected / at risk
Vomiting	Gastrointestinal disorders	0% THC With 0.065 g/dL BAC: 3 / 29 · 2.5-3.5% THC With 0.065 g/dL BAC: 0 / 27 · 6.0-7.5% THC and 0.065 g/dL BAC: 4 / 24 · 2.5-3.5% THC With 0 g/dL BAC: 0 / 26 · 6.0-7.5% THC With 0 g/dL BAC: 1 / 31 · 0% THC With 0 g/dL BAC: 0 / 27
Nausea	Gastrointestinal disorders	0% THC With 0.065 g/dL BAC: 0 / 29 · 2.5-3.5% THC With 0.065 g/dL BAC: 1 / 27 · 6.0-7.5% THC and 0.065 g/dL BAC: 3 / 24 · 2.5-3.5% THC With 0 g/dL BAC: 0 / 26 · 6.0-7.5% THC With 0 g/dL BAC: 0 / 31 · 0% THC With 0 g/dL BAC: 0 / 27
Tooth Ache	Gastrointestinal disorders	0% THC With 0.065 g/dL BAC: 1 / 29 · 2.5-3.5% THC With 0.065 g/dL BAC: 0 / 27 · 6.0-7.5% THC and 0.065 g/dL BAC: 0 / 24 · 2.5-3.5% THC With 0 g/dL BAC: 0 / 26 · 6.0-7.5% THC With 0 g/dL BAC: 0 / 31 · 0% THC With 0 g/dL BAC: 0 / 27
Loss of Consciousness	Nervous system disorders	0% THC With 0.065 g/dL BAC: 0 / 29 · 2.5-3.5% THC With 0.065 g/dL BAC: 1 / 27 · 6.0-7.5% THC and 0.065 g/dL BAC: 0 / 24 · 2.5-3.5% THC With 0 g/dL BAC: 0 / 26 · 6.0-7.5% THC With 0 g/dL BAC: 0 / 31 · 0% THC With 0 g/dL BAC: 0 / 27
Loss of Consciousness with IV Insertion	Nervous system disorders	0% THC With 0.065 g/dL BAC: 0 / 29 · 2.5-3.5% THC With 0.065 g/dL BAC: 0 / 27 · 6.0-7.5% THC and 0.065 g/dL BAC: 0 / 24 · 2.5-3.5% THC With 0 g/dL BAC: 0 / 26 · 6.0-7.5% THC With 0 g/dL BAC: 1 / 31 · 0% THC With 0 g/dL BAC: 0 / 27
Disorientation	Nervous system disorders	0% THC With 0.065 g/dL BAC: 0 / 29 · 2.5-3.5% THC With 0.065 g/dL BAC: 0 / 27 · 6.0-7.5% THC and 0.065 g/dL BAC: 0 / 24 · 2.5-3.5% THC With 0 g/dL BAC: 0 / 26 · 6.0-7.5% THC With 0 g/dL BAC: 1 / 31 · 0% THC With 0 g/dL BAC: 0 / 27
Dizziness	Nervous system disorders	0% THC With 0.065 g/dL BAC: 0 / 29 · 2.5-3.5% THC With 0.065 g/dL BAC: 2 / 27 · 6.0-7.5% THC and 0.065 g/dL BAC: 2 / 24 · 2.5-3.5% THC With 0 g/dL BAC: 0 / 26 · 6.0-7.5% THC With 0 g/dL BAC: 1 / 31 · 0% THC With 0 g/dL BAC: 0 / 27
Light-Headed	Nervous system disorders	0% THC With 0.065 g/dL BAC: 0 / 29 · 2.5-3.5% THC With 0.065 g/dL BAC: 2 / 27 · 6.0-7.5% THC and 0.065 g/dL BAC: 0 / 24 · 2.5-3.5% THC With 0 g/dL BAC: 0 / 26 · 6.0-7.5% THC With 0 g/dL BAC: 0 / 31 · 0% THC With 0 g/dL BAC: 0 / 27
Anxiety	Nervous system disorders	0% THC With 0.065 g/dL BAC: 0 / 29 · 2.5-3.5% THC With 0.065 g/dL BAC: 1 / 27 · 6.0-7.5% THC and 0.065 g/dL BAC: 4 / 24 · 2.5-3.5% THC With 0 g/dL BAC: 0 / 26 · 6.0-7.5% THC With 0 g/dL BAC: 0 / 31 · 0% THC With 0 g/dL BAC: 0 / 27
Headache	Nervous system disorders	0% THC With 0.065 g/dL BAC: 0 / 29 · 2.5-3.5% THC With 0.065 g/dL BAC: 0 / 27 · 6.0-7.5% THC and 0.065 g/dL BAC: 0 / 24 · 2.5-3.5% THC With 0 g/dL BAC: 0 / 26 · 6.0-7.5% THC With 0 g/dL BAC: 0 / 31 · 0% THC With 0 g/dL BAC: 0 / 27
Change in Status Perception	Nervous system disorders	0% THC With 0.065 g/dL BAC: 0 / 29 · 2.5-3.5% THC With 0.065 g/dL BAC: 1 / 27 · 6.0-7.5% THC and 0.065 g/dL BAC: 1 / 24 · 2.5-3.5% THC With 0 g/dL BAC: 0 / 26 · 6.0-7.5% THC With 0 g/dL BAC: 0 / 31 · 0% THC With 0 g/dL BAC: 0 / 27
Diaphoresis	Nervous system disorders	0% THC With 0.065 g/dL BAC: 0 / 29 · 2.5-3.5% THC With 0.065 g/dL BAC: 1 / 27 · 6.0-7.5% THC and 0.065 g/dL BAC: 0 / 24 · 2.5-3.5% THC With 0 g/dL BAC: 0 / 26 · 6.0-7.5% THC With 0 g/dL BAC: 0 / 31 · 0% THC With 0 g/dL BAC: 0 / 27
Incontinence	Renal and urinary disorders	0% THC With 0.065 g/dL BAC: 0 / 29 · 2.5-3.5% THC With 0.065 g/dL BAC: 1 / 27 · 6.0-7.5% THC and 0.065 g/dL BAC: 0 / 24 · 2.5-3.5% THC With 0 g/dL BAC: 0 / 26 · 6.0-7.5% THC With 0 g/dL BAC: 0 / 31 · 0% THC With 0 g/dL BAC: 0 / 27

Effects of Inhaled Cannabis on Driving Performance

Registry results are available

Study at a glance

Related local records

Conditions

Cannabinoids and active compounds

Medicines

What was registered

Alcohol(oral) and placebo

Cannabis(THC)(Inhaled) and Placebo

Results posted to the registry

Population and criteria

Inclusion criteria

Exclusion criteria

primary measures

Driving Performance

secondary measures

THC Concentration in Plasma Sample

THC Concentration Levels in Whole Blood

Locally readable linked articles

Overall Study

Age, Categorical

Sex: Female, Male

Ethnicity (NIH/OMB)

Race (NIH/OMB)

Region of Enrollment

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