A Phase 1 interventional study of Nicotine 0.05 mg/pulse and 0.1 mg/pulse and Saline Placebo (0.5mL injection) in Smoking ( Cigarette), sponsored by Yale University. Not yet recruiting at 1 site in United States. Open to participants aged 21 Years to 59 Years. Per ClinicalTrials.gov, last updated 2026-08-31.
Sponsored by Yale University · Phase 1, Interventional, and Health services research
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.
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).
475 studies on the registry are indexed under Cigarette Smoking; 86 are open to participants now.
This study's planned enrollment of 36 is below the median of 96 across 406 interventional studies indexed under Cigarette Smoking.
Browse Cigarette Smoking studies →Yale University is the lead sponsor of 1,770 studies on the registry; 294 are open to participants now.
Of its 221 completed or terminated interventional studies of FDA-regulated products, 129 (58%) have results posted.
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Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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
Saline (sugar water)
Drug: Saline Placebo (0.5mL injection)
participants practice using the e-cigarette and sample the sweet (sucralose) and control (unsweetened) flavors
Dietary Supplement: sucralose
participants practice using the e-cigarette and sample the sweet (sucralose) and control (unsweetened) flavors
Dietary Supplement: Sugar syrup (Placebo)
Drug page: Nicotine
Nicotine will be used and compared to saline given by IV push by study physician
Saline will be used compared to the low dose of Nicotine given by IV push by study physician
sweet flavor (sucralose) compared to unsweetened flavor
Unsweetened flavor compared to the sweetened flavor sucralose.
Drug Discrimination Scale (DDS) score.
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.
Time frame: OnTest Days 1, 2, 3 and 4
Drug Effects Questionnaire (DEQ) pleasurable effects score
The DEQ pleasurable effects consists of 11 questions with total score range from 0-100. Higher scores indicate more positive effects.
Time frame: OnTest Days 1, 2, 3 and 4
Minnesota Nicotine Withdrawal Scale score
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.
Time frame: OnTest Days 1, 2, 3 and 4
Plan to share: No
No publications or documents are linked to this record.
Start is estimated for Sep 2026; primary completion for Sep 2029, 36 months later.
Of 19 phase 1 interventional studies under Cigarette Smoking, half reached primary completion within 16 months of starting (the median), counting those still running; a quarter within 8 and three quarters within 29. This study's planned 36 months is above that.
How these figures are worked out, and which studies are left out of them.
This study is not yet recruiting, as verified in Aug 2026. You cannot join it, but the record below documents what was studied.
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Studies of the drugs tested here: Nicotine · Trichlorosucrose