Impact of Sweeteners on the Addictive Threshold of Nicotine

August 26, 2026 updated by: Yale University
To determine if sucralose, an artificial sweetener, modulates nicotine threshold doses for discrimination, subjective-rewarding effects, and reinforcement in smokers with varying levels of dependence.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Not yet recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Participants will complete an Adaptation Session followed by four Test Days. The Adaptation Session will familiarize participants with all study procedures. On each Test Day, a specific intravenous nicotine dose (0.05 or 0.1 mg/pulse) is paired with either a sucralose or control flavor administered by an electronic cigarette. The experimental procedure begins with a sampling phase comparing the assigned nicotine dose against saline, each paired with the assigned flavor, followed by four trials to assess the participant's ability to discriminate between the two conditions. Subsequently, participants complete four Choice trials, where they will choose between receiving the assigned nicotine dose and saline. Reinforcement will be measured by the percentage of nicotine choices, while discrimination will be measured by the percentage of correctly identified infusions. Subjective rewarding effects will be assessed using the "Pleasurable Effects" composite score of the Drug Effects Questionnaire (DEQ).

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
36

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

  • Name: Stacy A Minnix, B.S.
  • Phone Number: 203--932-5711

Study Locations

  • United States
    • Connecticut
      • West Haven, Connecticut, United States, 06516
        • VA Hospital

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Smoking at least for one year and more frequently than once a week, smoking status confirmed with a semi-quantitative urine nicotine test. Smokers will be stratified by level of dependence, assessed with the FTND 29 low or no dependence ≤3 and moderate or high dependence ≥ 4.
  • In good health as verified by medical history, screening examination, and screening laboratory tests.
  • For women, report using acceptable birth control methods.

Exclusion Criteria:

  • History of major medical or psychiatric disorders that the physician investigator deems as contraindicated for the participant to be in the study;
  • regular current use of certain psychotropic medications (such as mood stabilizers, antipsychotics, or anxiolytics being prescribed to treat bipolar disorder, psychosis or anxiety spectrum disorders, respectively);
  • current untreated alcohol or substance use disorder for any other recreational or prescription drugs other than nicotine;
  • for women, pregnant as determined by pregnancy screening, or breastfeeding; and 5) seeking (or undergoing) treatment for tobacco dependence or smoking.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Health Services Research
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Active Comparator: Nicotine
These test days will evaluate two nicotine doses (0.05 mg/pulse and 0.1 mg/pulse)
Drug: Nicotine 0.05 mg/pulse and 0.1 mg/pulse
Nicotine will be used and compared to saline given by IV push by study physician
Placebo Comparator: saline
Saline (sugar water)
Drug: Saline Placebo (0.5mL injection)
Saline will be used compared to the low dose of Nicotine given by IV push by study physician
Placebo Comparator: unsweetened flavor
participants practice using the e-cigarette and sample the sweet (sucralose) and control (unsweetened) flavors
Dietary supplement: Sugar syrup (Placebo)
Unsweetened flavor compared to the sweetened flavor sucralose.
Active Comparator: sucralose
participants practice using the e-cigarette and sample the sweet (sucralose) and control (unsweetened) flavors
Dietary supplement: sucralose
sweet flavor (sucralose) compared to unsweetened flavor

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Drug Discrimination Scale (DDS) score.
Time Frame: OnTest Days 1, 2, 3 and 4
This scale asks the participants to select if they received Drug A or B and how confident they are in their selection on a scale of 0 to 10. Higher scores indicate more confidence.
OnTest Days 1, 2, 3 and 4
Drug Effects Questionnaire (DEQ) pleasurable effects score
Time Frame: OnTest Days 1, 2, 3 and 4
The DEQ pleasurable effects consists of 11 questions with total score range from 0-100. Higher scores indicate more positive effects.
OnTest Days 1, 2, 3 and 4

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Minnesota Nicotine Withdrawal Scale score
Time Frame: OnTest Days 1, 2, 3 and 4
This 8-item scale will be used to assess DSM-IV symptoms of nicotine withdrawal. Total score range 0-32. Higher scores indicate more severe withdrawal symptoms.
OnTest Days 1, 2, 3 and 4

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Yale University

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
National Institute on Drug Abuse (NIDA)

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Mehmet Sofuoglu, M.D., Ph.D., Yale University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
September 1, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
September 1, 2029

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 31, 2029

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
August 13, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
August 13, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
August 18, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
August 31, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
August 26, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
August 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 2000043445
  • 2U54DA036151-11 (U.S. NIH Grant/Contract: NIH)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

Cookie Settings

We use cookies to ensure that we give you the best experience on our website. For more details carefully read our Privacy and Cookies Policy. ...>>>You can change your preferences or withdraw your consent at any time by deleting the cookies from your website or computer as described in the policy. Please accept it and choose your preferences by ticking the corresponding boxes in the "Manage Settings" section below. Please carefully read our Terms of Service before you proceed with using any part of this website.
«Manage Settings