for people ages 21 years and up (full criteria)
healthy people welcome
at San Francisco, California and other locations
study started
estimated completion:
Neal L. Benowitz



This is an observational, crossover study that will be examine use behaviors, chemical exposures, and biological effects of SREC compared to TC use in subjects confined to a research ward setting.


Daily cigarette smokers who are familiar with e-cigarette (EC) use will be instructed to use only NIDA Standardized Research Electronic Cigarettes (SREC) and tobacco cigarettes (TC) while enrolled on the study. The overall goals are two-fold: (1) to compare nicotine and toxicant exposure and pharmacological effects of SREC used alone vs tobacco cigarettes (TC); and (2) using scheduled SREC use combined with ad libitum TC use as a model for dual use, to examine the extent to which nicotine and toxicant exposure and biomarkers of potential harm compare with dual use vs TC alone use. The former would inform the effects of total switching, the latter would inform the potential harm reducing effects of smoking fewer TC while using EC.


Nicotine Dependence Tobacco Toxicity Nicotine Dependence, Cigarettes Cardiovascular Risk Factor Nicotine Withdrawal nicotine tobacco research electronic cigarette e-cigarette SREC Tobacco Use Disorder Standardized Dual Use


You can join if…

Open to people ages 21 years and up

  • Healthy on the basis of medical history and limited physical examination as described below:

Heart rate < 105 BPM; Systolic Blood Pressure < 160 and >90; Diastolic Blood Pressure < 100 and > 50; Body Mass Index ≤ 38.0

  • Current regular "dual" user of both EC:

using an EC at least once in the past 30 days; daily use of conventional TC (at least 5 CPD, as confirmed by saliva cotinine >50 ng/ml and/or NicAlert=6)

You CAN'T join if...

  • Unstable medical conditions (such as unstable heart disease, uncontrolled hypertension, thyroid disease, diabetes, Hepatitis B or C or renal or liver impairment, glaucoma, or prostatic hypertrophy).
  • Psychiatric conditions (such as current or past schizophrenia and/or current or past bipolar disorder, adult onset ADHD (if being treated). Participants with current or past depression and/or anxiety disorders will be reviewed by the study physician and considered for inclusion. Psychiatric hospitalizations are not exclusionary, but study participation will be determined as per study physician's approval.
  • Psychiatric medications with the exception of SSRIs and SNRIs and current evaluation by the study physician that the participant is otherwise healthy, stable and able to participate.
  • Pregnancy or breastfeeding (by history and pregnancy test)
  • 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 15 times in combination in the past month and must agree to abstain from their use during the period of the study.]
  • Concurrent use of nicotine-containing medications
  • Alcohol or illicit drug dependence within the past 12 months (with the exception of those who have recently completed an alcohol/drug treatment program) or current illicit drug use (by history or urine test). Any methadone replacement therapy.
  • Medications: Use of medications that are inducers of nicotine metabolizing enzyme

CYP2A6 (Example: rifampicin, dexamethasone, phenobarbital, and other anticonvulsant drugs). Use of medications for cardiovascular conditions including hypertension(Example: beta and alphablocking drugs).

  • Other/Misc Health Conditions: Oral thrush; fainting; untreated thyroid disease; other"life threatening illnesses" as per study physician's discretion.
  • Concurrent participation in another clinical trial
  • Inability to communicate in English


  • UCSF Tobacco Research Center not yet accepting patients
    San Francisco California 94110 United States
  • Zuckerberg San Francisco General Hospital - CTSI
    San Francisco California 94110 United States

Lead Scientist

  • Neal L. Benowitz
    Neal Benowitz has been conducting research at SFGH since 1973. His research focus is on the human pharmacology of nicotine in relation to pathogenesis of and individual differences in vulnerability to tobacco-related disease, and the use of pharmacologic data as a basis for public health policies to prevent and reduce such disease.


not yet accepting patients
Start Date
Completion Date
University of California, San Francisco
Study Type
Last Updated