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

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

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).

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