Combining Varenicline and Guanfacine for Smoking Cessation

The novel design of this study combines a laboratory paradigm to evaluate stress-induced smoking behavior and smoking-related reinforcement, followed by a 12-week treatment phase to evaluate clinical outcomes.

Study Overview

• Status: Completed
• Conditions: Smoking Cessation
• Intervention / Treatment: Drug: Varenicline; Drug: Guanfacine ER

Detailed Description

Using a double-blind, this Phase 2 study will randomize 140 smokers to a parallel group design (varenicline + guanfacine vs. varenicline alone). Following titration to steady state levels, the investigators will evaluate sex differences in medication effects on stress-induced smoking behavior and smoking-related reinforcement in the laboratory, and on abstinence outcomes during a subsequent 12-week treatment period.

• Study Type: Interventional
• Enrollment (Actual): 167
• Phase: Phase 2

Contacts and Locations

Study Locations

• United States
  • Connecticut
    • New Haven, Connecticut, United States, 06519
      • Yale University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

1. Age 18+
2. Able to read and write English
3. SMOKER: 10 or more cigarettes per day for at least the past year, Carbon Monoxide (CO) > 10 ppm at intake
4. Able to take oral medications and willing to adhere to medication regimen
5. Provide evidence of a stable living residence in the last 2 months prior to randomization, have reasonable transportation arrangements to the study site, have no plans to move within the next 3 months, and have no unresolved legal problems
6. Motivated to quit smoking (8 or greater on the Contemplation Ladder)

Exclusion Criteria:

1. Subjects with any significant current medical conditions (neurological, cardiovascular [including hypertension or hypotension: sitting BP >160/100 or <90/60mmHg at baseline screening], endocrine, thyroid, renal, liver), seizures, delirium or hallucinations, or other unstable medical conditions
2. Current Diagnostic and Statistical Manual of Mental Disorders (DSM-V) alcohol or substances use disorders, other than mild alcohol use disorder or tobacco use disorder
3. Subjects who have a positive test result at intake appointment on urine drug screens conducted for illicit drugs
4. Past 30 day use of psychoactive drugs excluding anxiolytics and antidepressants (however, see #10; barbiturates, benzodiazepines are exclusionary)
5. Women who are pregnant or nursing, or fail to use one of the following methods of birth control unless she or partner is surgically sterile or she is postmenopausal (hormone contraceptives [oral, implant, injection, patch, or ring], contraceptive sponge, double barrier [diaphragm or condom plus spermicide], or IUD)
6. Suicidal, homicidal or evidence of current (past 6-month) severe mental illness such as schizophrenia or bipolar disorder
7. meeting DSM-V criteria for current (past-6 month) attention deficit hyperactivity disorder (ADHD)
8. Individuals who are currently taking medications known to be effective for smoking cessation (e.g., FDA smoking cessation medications, nortriptyline, clonidine) or are regular users of e-cigarettes or other tobacco projects (pipe, cigar, smokeless tobacco) in the past 30 days
9. Only one member per household can participate in the study
10. Specific exclusions for administration of guanfacine not already specified: EKG evidence at baseline screening of any clinically significant conduction abnormalities or arrhythmias; known intolerance for guanfacine or any alpha blocker; history of fainting, syncopal attacks, heart failure or myocardial infarction, or impaired liver (aspartate aminotransferase [AST], alanine aminotransferase [ALT] > 3x normal) or renal function (estimated creatinine clearance <60 cc/min); treatment with any antihypertensive drug or any alpha-blocker; use of any central nervous system (CNS) depressant (e.g., phenothiazines, barbiturates, benzodiazepines)
11. Specific exclusions for the administration of varenicline not already specified: known intolerance to varenicline or taking H2blockers (e.g., Cimetidine), quinolones, or trimethoprim.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Quadruple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Varenicline + Guanfacine ER; Varenicline (2mg/day) + Guanfacine extended release (6mg/day ER). Varenicline (2mg/day) administered orally twice a day at 8:00 AM and 8:00 PM while titrating to full dose. Titration schedule: Days 1-9 0mg/day; 0mg/dose, Days 10-12 0.5mg/day; 0.5mg/dose 8:00 PM, Days 13-15 1mg/day; 0.5mg/dose, Days 16-21 2mg/day; 1mg/dose. Guanfacine ER (6mg/day) administered orally twice daily at 8:00 AM and 8:00 PM while titrating to the full dose. Titration schedule: Days 1-3 1mg/day; 0.5mg/dose, Days 4-6 2mg/day; 1mg/dose, Days 7-9 3mg/day; 1.5mg/dose, Days 10-12 4mg/day; 2mg/dose; Days 13-15 5mg/day; 2.5mg/dose and Days 16-23 6mg/day; 3mg/dose. Once at steady state, administration is orally once per day at 8:00 PM for both medications.	Drug: Varenicline; Varenicline 2mg/day; Other Names: Chantix; Drug: Guanfacine ER; Guanfacine Extended Release (6mg/day ER); Other Names: Intuniv
Active Comparator: Varenicline; Varenicline (2mg/day). Varenicline (2mg/day) administered orally twice a day at 8:00 AM and 8:00 PM while titrating to full dose. Titration schedule: Days 1-9 0mg/day; 0mg/dose, Days 10-12 0.5mg/day; 0.5mg/dose 8:00 PM, Days 13-15 1mg/day; 0.5mg/dose, Days 16-21 2mg/day; 1mg/dose. Once at steady state, administration is orally once per day at 8:00 PM.	Drug: Varenicline; Varenicline 2mg/day; Other Names: Chantix

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Latency	Latency (in minutes) to time of first cigarette smoked during the 50-minute delay period.	minutes (range 0 to 50 min)

Collaborators and Investigators

• Sponsor: Yale University
• Collaborators: National Institute on Drug Abuse (NIDA)
• Investigators: Principal Investigator: Sherry McKee, PhD, Yale University

Study record dates

Study Major Dates

• Study Start (Actual): November 1, 2020
• Primary Completion (Actual): April 30, 2025
• Study Completion (Actual): April 30, 2025

Study Registration Dates

• First Submitted: December 3, 2019
• First Submitted That Met QC Criteria: December 11, 2019
• First Posted (Actual): December 13, 2019

Study Record Updates

• Last Update Posted (Actual): June 9, 2026
• Last Update Submitted That Met QC Criteria: May 13, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Behavior; Health Behavior; Smoking Cessation; Organic Chemicals; Heterocyclic Compounds; Heterocyclic Compounds, 2-Ring; Heterocyclic Compounds, Fused-Ring; Carboxylic Acids; Benzazepines; Guanidines; Amidines; Acids, Carbocyclic; Quinoxalines; Phenylacetates; Varenicline; Guanfacine
• Other Study ID Numbers: 2000026630; R01DA047986 (U.S. NIH Grant/Contract)

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