Overview

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.

Eligibility

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
        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