Overview
This study will examine the short-term cardiovascular (CV) effects of e-liquid pH in a randomized, crossover clinical and behavioral pharmacology study of experienced adult e-cigarette users (N=21). The specific aim of the study is to assess the impact of changes in e-liquid pH on nicotine pharmacokinetics, cardiovascular, and subjective effects of e-cigarettes.
Description
This is a single-site, randomized, crossover study of experienced adult e-cigarette users to assess nicotine exposure, toxicant exposure, and the short-term CV effects of e-liquid pH. Three e-liquid pH conditions will be assessed on all participants: 5, 7, and 9.
Hypothesis 2a: The rate of systemic nicotine absorption is inversely related to e-liquid pH and results in lower peak blood nicotine levels at higher pH.
Hypothesis 2b: Heart rate acceleration will decrease and subjective measures of sensation in the throat, reward, and satisfaction will increase with increasing e-liquid pH.
Eligibility
Inclusion Criteria:
- Heart rate < 105 beats per minute (BPM)*
- Systolic Blood pressure <160 and > 90*
- Diastolic Blood Pressure <100 and > 50*
- Body Mass Index (BMI) < 38.0 (at investigator's discretion for higher BMI if no other
concurrent health issues)
*considered out of range if both machine and manual readings are above/below these thresholds
- Use e-cigarettes on at least 15 days in the past 30 for at least 3 months
- Smoke 10 or fewer cigarettes/tobacco products per day in the last 30 days
- Willing to use mod e-cigarette
- Willing to abstain from tobacco product use for night before study
- Age: > 21 years old and < 70 years old
- Using e-liquid > 0mg/ml nicotine
- Saliva cotinine of ≥ 30 ng/ml or NicAlert=6 (in cases where lab turn around time will delay study procedure)
Exclusion Criteria:
- Seizures
- Cancer
- Hepatitis B or C or Liver Disease
- Oral Thrush
- Heart disease
- Glaucoma
- Kidney disease or urinary retention
- Diabetes
- High Blood Pressure (taking sympatholytic medications such as alpha and beta blockers)
- History of stroke
- An ulcer in the past year
- Thyroid disease (okay if controlled with medication)
- Active use of an inhaler for asthma or Chronic Obstructive Pulmonary Disease (COPD)
- Psychiatric conditions
- Current or past schizophrenia, and/or current or past bipolar disorder
- Major depression, current or within the past year
- Major personality disorder
- Participants with current or past minor or moderate 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
- Recent onset or change in cough, fever and/or abdominal symptoms (vomiting or pain) in the past two weeks. (If yes, participant can re-screen when symptoms resolve).
- 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)
- Opioid replacement therapy (including methadone, buprenorphine, or other)
- Positive urine cannabis is not exclusionary but participant must report use of cannabis and agree to abstain from cannabis use for the duration of the study
- Psychiatric medications
- Current regular use of any psychiatric medications with the exception of Selective Serotonin Reuptake Inhibitor (SSRI) and serotonin-norepinephrine reuptake Inhibitor (SNRIs) and current evaluation by the study physician that the participant is otherwise healthy, stable, and able to participate.
- Medications
- Use of medications that are inducers of nicotine metabolizing enzyme CYP2A4 (Example: rifampicin, carbamazepine, phenobarbital, and other anticonvulsant drugs).
- Concurrent use of nicotine-containing medications
- Any stimulant medications (example: Adderall) generally given for Attention deficit hyperactivity disorder (ADHD) treatment
- Use of sympatholytic medications that affect cardiovascular conditions including hypertension, (Example: beta and alpha-blockers)
- Other/Misc. Chronic Health Conditions
- Fainting (within the last 30 days)
- Other "life threatening illnesses" as per study physician's discretion
- Pregnancy
- Pregnancy (self-reported and urine pregnancy test)
- Breastfeeding (determined by self-report)
- Concurrent participation in another clinical trial
- Inability to communicate in English
- Planning to quit vaping within the next 60 days
- Uncomfortable with getting blood drawn