vaping high vs. low nicotine e-liquid

Conditions: Cardiovascular Risk Factor; Nicotine Dependence

Summary: this study will examine the effects of electronic cigarette e-liquid nicotine content in a randomized, crossover clinical and behavioral pharmacology study of experienced adult e-cigarette users (n=36). the specific aim is to determine the impact of nicotine content of e-liquid on nicotine pharmacology, systemic exposure to toxic volatile organic compounds, and short-term cardiovascular effects.

this is a within-subjects, crossover design of advanced electronic cigarette users in which we will examine nicotine pharmacokinetics, subjective effects, daily nicotine intake and nicotine titration, short-term cardiovascular effects, and toxicant exposure when participants are using low vs. high nicotine e-liquids. hypothesis 1: e-cigarette users will titrate their intake of nicotine such that they will inhale fewer aerosol toxicants and suffer less harm to health when using higher vs. lower nicotine content e-liquids. hypothesis 2: compared to low nicotine, high nicotine e-liquid use will have similar cardiovascular effects throughout the day (due to compensatory behavioral changes), with similar effects on heart rate, blood pressure, and catecholamine release. hypothesis 3: exposure to volatile organic compounds (vocs) will be lower when vaping high nicotine e-liquids compared to low nicotine e-liquids.

Eligibility criteria:
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 \ 90\* * diastolic blood pressure \ 50\* \*considered out of range if both machine and manual readings are above/below these thresholds. * age: \>= 21 years * age: \<= 70 years * current regular user of open tank electronic cigarette (ec) (at least 20 times in the past 30 days) with e-liquid nicotine of 3-6 mg/ml. * non-smoker or non-daily cigarette smokers agreeing to abstain from cigarettes for the duration of the study. * saliva cotinine \>50 ng/ml and/or nicalert=6 * carbon monoxide \>= 5 ppm or per discretion of principal investigator exclusion criteria: * medical * heart disease * seizures * cancer * thyroid disease (okay if controlled with medication) * diabetes * hepatitis b or c or liver disease * glaucoma * kidney disease or urinary retention * history of stroke * an ulcer in the past year * 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 pi and considered for inclusion * history of psychiatric hospitalizations is not exclusionary, but study participation will be determined as per pi's approval * 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 for illicit drugs at the screening visit (thc \& prescribed medications okay) * opioid replacement therapy (including methadone, buprenorphine, or other) * psychiatric medications * current regular use of any psychiatric medications with the exception of selective serotonin reuptake inhibitors (ssris) and serotonin-norepinephrine reuptake inhibitors (snris) and current evaluation by the pi that the participant is otherwise healthy, stable, and able to participate. * medications * use of medications that are inducers of nicotine metabolizing enzyme cyp2a6 (example: rifampicin, carbamazepine, phenobarbital, and other anticonvulsant drugs). * use of sympatholytic medications for cardiovascular conditions including hypertension (example: beta and alpha-blockers) * concurrent use of nicotine-containing medications * any stimulant medications (example: adderall) generally given for attention deficit hyperactivity disorder (adhd) treatment * other/misc. chronic health conditions * oral thrush * fainting (within the last 30 days) * other "life threatening illnesses" as per pi's discretion * pregnancy * pregnancy (self-reported and urine pregnancy test) * breastfeeding (determined by self-report) * concurrent participation in another clinical trial * inability to read and write in english * planning to quit vaping within the next 60 days * concurrent regular use of marijuana (occasional users of these products may be enrolled if they agree to abstain from their use during the period of the study) * use of other tobacco products, smokeless tobacco, pipes, cigars/cigarillos, blunts/spliffs (no more than 10 times in the past month and must agree to abstain from their use during the period of the study)

Keywords: e-cigarettes vaping e-cig mods e-liquid