Effects of Inhaled Cannabis on Driving Performance

Not Applicable

Completed

Conditions: Cannabis
Alcohol Drinking

Interventions: Drug: Alcohol(oral) and placebo
Drug: Cannabis(THC)(Inhaled) and Placebo

Registration Number: NCT01620177

Lead Sponsor: Gary R Gaffney

Brief Summary: 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.

Detailed Description: 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.

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 98

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
If female, pregnant or nursing
Currently interested in or participating in drug abuse treatment, or participated in drug abuse treatment within 60 days preceding study enrollment
Currently taking drugs that are contraindicated for use with study drugs
Requires any special equipment to aid in driving (ex. pedal extensions, hand brake or throttle, spinner wheel knobs or other non-standard equipment)
Significant history of motion sickness or demonstrates significant simulator sickness during practice drives at screening (SSQ). Subjects must have scores below the following values on the SSQ: Nausea < 21, Oculomotor <32, Disorientation < 15, and Total Score < 32.
Current alcohol or cannabis use disorder, as identified by the Alcohol Use Disorders Identification Test for alcohol or Cannabis Use Disorders Identification Test for cannabis.
History of any illness that, in the opinion of the study investigator, might confound the results of the study or pose an additional risk to the subject from study participation
Prior participation in a driver impairment or distraction-related research study conducted at NADS that uses the same base drive.

Study & Design

Study Type: INTERVENTIONAL

Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
0% THC with 0.065 g/dL BAC	Cannabis(THC)(Inhaled) and Placebo	-
0% THC with 0.065 g/dL BAC	Alcohol(oral) and placebo	-
2.5-3.5% THC with 0.065 g/dL BAC	Cannabis(THC)(Inhaled) and Placebo	-
6.0-7.5% THC with 0 g/dL BAC	Alcohol(oral) and placebo	-
2.5-3.5% THC with 0.065 g/dL BAC	Alcohol(oral) and placebo	-
6.0-7.5% THC and 0.065 g/dL BAC	Alcohol(oral) and placebo	-
2.5-3.5% THC with 0 g/dL BAC	Cannabis(THC)(Inhaled) and Placebo	-
6.0-7.5% THC with 0 g/dL BAC	Cannabis(THC)(Inhaled) and Placebo	-
0% THC with 0 g/dL BAC	Alcohol(oral) and placebo	-
0% THC with 0 g/dL BAC	Cannabis(THC)(Inhaled) and Placebo	-
6.0-7.5% THC and 0.065 g/dL BAC	Cannabis(THC)(Inhaled) and Placebo	-
2.5-3.5% THC with 0 g/dL BAC	Alcohol(oral) and placebo	-

Primary Outcome Measures

Name	Time	Method
Driving Performance	Through entire drive, 0.5-1.3 hr post cannabis administration.	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.

Secondary Outcome Measures

Name	Time	Method
THC Concentration in Plasma Sample	-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	-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.