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

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 used * Saliva cotinine \>= 50 ng/ml and/or NicAlert = 6 * Age \>= 21 years old \<= 70 years old * Willingness to abstain from drug use for the duration of the study Exclusion Criteria: * The following unstable medical conditions: * 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) * 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 medi…