Pharmacokinetics and Pharmacodynamics of Nicotine With Use of Standardized Research Electronic Cigarette (SREC)

This is a crossover study that will examine use behaviors, chemical exposures, and biological effects of Standardized Research Electronic Cigarette (SREC) compared to usual brand e-cigarette use in natural or synthetic nicotine users.

Inclusion Criteria:Healthy on the basis of medical history and limited physical examination-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.Body Mass Index <= 38.0.Current regular user of electronic cigarettes (EC)EC device use at least 15 or more days in the past 30 days (with e- liquid >= 3mg/ml)No restriction on flavor or type of e-cigarette usedSaliva cotinine >= 50 ng/ml and/or NicAlert = 6Age >= 21 years old <= 70 years oldWillingness to abstain from drug use for the duration of the studyExclusion Criteria:The following unstable medical conditions:Heart diseaseSeizuresCancerThyroid disease (okay if controlled with medication)DiabetesHepatitis B or C or Liver diseaseGlaucomaKidney disease or urinary retentionHistory of strokeAn ulcer in the past yearActive use of an inhaler for Asthma or chronic obstructive pulmonary disease (COPD)MedicationsUse 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 (Example: nicotine patch, lozenge, gum).Any stimulant medications (example: Adderall) generally given for attention deficit hyperactivity disorder (ADHD) treatment.Other/Misc. Health ConditionsOral thrushFainting (within the last 30 days)Other "life threatening illnesses" as per principal investigator and/or study physician's discretionPregnancyPregnancy (self-reported and urine pregnancy test)Breastfeeding (determined by self-report)Women of childbearing potential must be using an acceptable method of contraceptionConcurrent participation in another clinical trial.Inability to read and write in EnglishPlanning to quit smoking or vaping within the next 60 daysA known propylene glycol/vegetable glycerin allergyUncomfortable with getting blood drawnRecent onset or change (worsening) in cough, fever and/or abdominal symptoms (vomiting or pain) in the past two weeks