short-term cardiovascular effects of e-cigarettes: influence of e-liquid ph

Conditions: Cardiovascular Risk Factor; Nicotine Dependence

Summary: 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.

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 criteria:
inclusion criteria: * heart rate \< 105 beats per minute (bpm)\* * systolic blood pressure \ 90\* * diastolic blood pressure \ 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

Keywords: e-cigarettes vaping e-cig mods