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Completed

NCT Number: NCT04095104

Adjunct Phentermine + Topiramate After Bariatric Surgery in 12-24 Year Olds

The goal of this pilot study is to establish the feasibility and initial efficacy of the combination of phentermine and topiramate for adolescents and young adults who require additional risk reduction after bariatric surgery. This study will use a randomized, placebo-controlled, double-blinded design to evaluate an adjunctive 12-week intervention of phentermine + topiramate + standard of care vs. placebos + standard of care 6 months after bariatric surgery, among 12 to 24 year olds who don't achieve expected weight loss or who remain severely obese (n=10 total).

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Key information

Age range

12 year–24 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 2

Primary location

Children's Hospital Colorado

Aurora, Colorado, 80045, United States

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Status post sleeve gastrectomy or roux-en-y gastric bypass
  • At 6 months after bariatric surgery, has not achieved >= 26% decrease in weight from preoperative weight (within 1 week of surgery) OR remains severely obese (>=120% of 95th%ile or BMI >=35kg/m2 for 12-17yo; BMI >=35kg/m2 for 18-24yo)

Exclusion criteria

  • Absolute contraindication to phentermine or topiramate (i.e. phentermine:

history of coronary artery disease, stroke, arrhythmia, congestive heart failure, uncontrolled hypertension), hypersensitivity to sympathomimetic amines, current or recent (within 14 days) use of monoamine oxidase inhibitors, glaucoma, or hyperthyroidism; topiramate: hypersensitivity to topiramate, history of nephrolithiasis)

  • Concomitant use of phenytoin, carbamazepine, or carbonic anhydrase inhibitors (e.g. zonisamide, acetazolamide, or dichlorphenamide)
  • Use of anti-obesity medication within 6 months of screening
  • Initiation of a new medication associated with weight loss or gain within 30 days of screening
  • Type 2 diabetes mellitus
  • Hypothalamic obesity
  • Unmanaged (e.g. without medications and/or psychotherapy) clinically significant (determined by a mental health professional using diagnostic instruments and/or clinical interview) depression or anxiety
  • History of any suicidal behavior within 30 days of screening or any suicidal ideation with either some intent to act or with intent and a specific plan within 30 days of screening
  • History of schizophrenia
  • Severe hepatic impairment (ALT >10x upper limit of normal or known synthetic liver dysfunction)
  • Moderate or severe renal impairment (GFR <30mL/min/1.73m2)
  • Dosage change to hypertension, dyslipidemia, depression, or anxiety medication <4 weeks prior to study enrollment
  • Contraception started <7 days prior to study enrollment
  • Current pregnancy/plans to become pregnant within 16 weeks from study drug start date
  • Females without a long acting reversible contraceptive (LARC) who do not commit to using 2 forms of birth control

Treatment and study plan

Phentermine

Drug

Phentermine tablet

Other names: Lomaira, Adipex-P, C045TQL4WP, 2-methyl-1-phenylpropan-2-amine

Immediate Release Topiramate

Drug

Topiramate tablet

Other names: Topamax, 0H73WJJ391, [(3aS,5aR,8aR,8bS)-2,2,7,7-tetramethyl-5,5a,8a,8b-tetrahydrodi[1,3]dioxolo[4,5-a:5',3'-d]pyran-3a-yl]methyl sulfamate

Placebo for Phentermine

Drug

Compounded tablet to mimic phentermine 8mg tablet

Placebo for Immediate Release Topiramate

Drug

Compounded tablet to mimic immediate release topiramate 25mg tablet

Primary outcomes

  1. Enrollment Rate

    Time frame: 6 months

    (Number enrolled divided by number eligible) x 100

  2. Dropout Rate

    Time frame: 24 months

    Number who do not complete the study divided by number enrolled

  3. Number of Participants Adherent to Study Drugs

    Time frame: 12 weeks

    Presence of amphetamine in the urine at any study visit

  4. Frequency of Adverse Events

    Time frame: 24 months

    Unique adverse events documented prior to unblinding. Adverse events were elicited using a standardized checklist during study phone calls and in-person study visits, laboratory monitoring, review of systems, vitals, physical exam, and mood/suicidality assessment using validated instruments at every study visit.

Secondary outcomes

  1. Percent BMI Change

    Time frame: Baseline and 12 weeks

    (Baseline BMI - BMI at 12 weeks)/Baseline BMI x 100

  2. Percent Weight Change

    Time frame: Baseline and 12 weeks

    (Baseline weight - weight at 12 weeks)/Baseline weight x 100

  3. Change in BMI Percent of the 95th%Ile

    Time frame: Baseline and 12 weeks

    (Baseline BMI % of the 95th%ile - BMI % of the 95th%ile at 12 weeks)

  4. Change in Heart Rate

    Time frame: Baseline and 12 weeks

    (Heart rate at baseline - Heart rate at 12 weeks)

  5. Change in Systolic Blood Pressure

    Time frame: Baseline and 12 weeks

    Systolic blood pressure at baseline - Systolic blood pressure at 12 weeks

  6. Change in Diastolic Blood Pressure

    Time frame: Baseline and 12 weeks

    Diastolic blood pressure at baseline - Diastolic blood pressure at 12 weeks

  7. Change in Total Cholesterol (mg/dL)

    Time frame: Baseline and 12 weeks

    Total cholesterol at baseline - Total cholesterol at 12 weeks

  8. Change in Triglycerides (mg/dL)

    Time frame: Baseline and 12 weeks

    Triglycerides at baseline - Triglycerides at 12 weeks

  9. Change in LDL Cholesterol (mg/dL)

    Time frame: Baseline and 12 weeks

    LDL at baseline - LDL at 12 weeks

  10. Change in HDL Cholesterol (mg/dL)

    Time frame: Baseline and 12 weeks

    HDL at baseline - HDL at 12 weeks

  11. Change in Alanine Aminotransferase (ALT) (U/L)

    Time frame: Baseline and 12 weeks

    ALT at baseline - ALT at 12 weeks

  12. Change in Hemoglobin A1c (HbA1c) (%)

    Time frame: Baseline and 12 weeks

    HbA1c at baseline - HbA1c at 12 weeks

  13. Change in % Fat Mass

    Time frame: Baseline and 12 weeks

    % Fat mass at baseline - %Fat mass at 12 weeks measured by DEXA

  14. Change in Resting Metabolic Rate (RMR)

    Time frame: Baseline and 12 weeks

    RMR at baseline - RMR at 12 weeks measured by indirect calorimetry

  15. Change in Daily Kilocalorie Intake

    Time frame: Baseline and 12 weeks

    The average kilocalorie intake of 3 days was calculated each at baseline and 12 weeks. Kilocalories were calculated based on a standardized self-reported log of two weekdays and 1 weekend day.

  16. Change in Hunger

    Time frame: Baseline and 12 weeks

    The adolescent/young adult will report subjective hunger before each meal and snack for 24 hours using a visual analogue slider scale (0= no hunger, 100 = most hunger) and this score will be averaged over the 24 hour period.

  17. Change in Satiety

    Time frame: Baseline and 12 weeks

    The adolescent/young adult will report subjective satiety 30 minutes after each meal and snack for 24 hours using a visual analogue slider scale (0= no fullness, 100 = most full) and this score will be averaged over the 24 hour period.

  18. Change in Eating in the Absence of Hunger

    Time frame: Baseline and 12 weeks

    Validated questionnaire: Eating in the Absence of Hunger-Parent (EAH-P) completed by the parent/guardian about their adolescent/young adult. This measure has 14 items.

    Each item is on a 5-point Likert scale ranging from 1= "never" to 5= "always". A higher score indicates more eating in the absence of hunger.

    Total scores (minimum 14 to maximum 70) are calculated by taking the sum of the 14 items at each time point.

    The mean change in total scores by group are presented.

  19. Change in Cognitive Restraint

    Time frame: Baseline and 12 weeks

    The "Three-Factor Eating Questionnaire" will be completed by the adolescent/young adult. This is a 51-item questionnaire that assesses 3 eating behaviors: Cognitive Dietary Restraint, Disinhibited Eating, and Predisposition to hunger. Cognitive restraint was the domain of highest interest for this study and is reported here. Higher scores in each domain indicate more of each of those behaviors.

    The cognitive restraint domain score is calculated by taking the average of the 21 items in that domain. Each of the 21 items has a score of 0 or 1.

    MINIMUM mean score for this measure is: 0 and MAXIMUM mean score is 1. MINIMUM total score for this measure is: 0 and MAXIMUM total score is 21 (relevant to the "Full Range" in the data table below)

  20. Change in Total Weight Related Quality of Life- Adolescent/Young Adult Report

    Time frame: Baseline and 12 weeks

    "Impact of Weight on Quality of Life-Kids" questionnaire will be completed by the adolescents age <=19.

    Total and each of the 4 sub scales (Physical Comfort-6 items, Body Esteem-9 items, Social Life-6 items, and Family Relations-6 items) range from a minimum score of 0 to a maximum of 100.

    Higher scores indicate higher quality of life.

  21. Change in Total Weight Related Quality of Life- Parent Reported of Adolescent/Young Adult

    Time frame: Baseline and 12 weeks

    "Impact of Weight on Quality of Life-Kids Parent Proxy" questionnaire will be completed by the parent of the adolescent/young adult.

    Total and each of the 4 sub scales (Physical Comfort-6 items, Body Esteem-9 items, Social Life-6 items, and Family Relations-6 items) range from a minimum score of 0 to a maximum of 100.

    Higher scores indicate higher quality of life.

  22. Change in General Health Related Quality of Life: Total Score PedsQL Instrument - Self Report

    Time frame: Baseline and 12 weeks

    PedsQL instrument will be completed by the adolescent/young adult. The CHANGE in total scale score is reported here. The total scale score at each time point ranges from a MIN of 0 to a MAX of 100.

    Items are rated on a 0-4 scale. Items are reverse scored and linearly transformed to a 0-100 scale, such that 0=100, 1=75, 2=50, 3=25, and 4=0.

    Scale Scores are calculated as the sum of the items over the number of items answered.

    Higher scores indicated better health-related quality of life.

  23. Change in Depression

    Time frame: Baseline and 12 weeks

    The adolescent/young adult will complete the 20-item Center for Epidemiologic Studies Depression Scale (CES-D).

    Each item is rated on a 0 to 3 scale (positive items are reverse scored). Minimum score is 0 and maximum is 60. Higher scores indicate more depressive symptoms. Total score is calculated by summing each of the 20 individual items scores.

  24. Participant Satisfaction: Questionnaire

    Time frame: At 12 weeks

    The participating family will be asked to complete a satisfaction questionnaire that will assess reasons for participation, experience during study visits, satisfaction with the effect of the study drug, ease of communication with study staff, and study burden.

    The outcome presented here is the average of the parent and adolescent/young adult dyad's response to the statement: "My overall experience was positive" [1=Strongly disagree, 5=Strongly agree]

Sponsors and collaborators

Lead sponsor

University of Colorado, Denver

Other

Collaborators

  • National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
  • University of Colorado- Clinical and Translational Sciences Institute
  • University of Colorado- Nutrition Obesity Research Center

Registry information

Official study title

Adjunctive Anti-Obesity Pharmacotherapy in Adolescents and Young Adults After Bariatric Surgery: A Randomized Controlled Pilot Study

Important dates

Study start
2020
Primary completion
2022
Study completion
2022
First posted
Sep 19, 2019
Registry last updated
May 23, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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