Peripheral Pharmacodynamics of Topiramate-Phentermine in Obese Patients
Trial status: Open for Enrollment
Why is this study being done?
Investigators propose a randomized controlled trial of combination phentermine topiramate versus placebo given orally for 10-15 days. Dosing of 3.75/23 mg days 1-5, increased to 7.5/46 mg days 6-14. Participants will be randomized according to a computer generated randomization schedule generated by the study statistician's office and submitted to the Mayo Clinic CTSA research pharmacy. Allocation will be concealed. The study blind will be retained until all the data on gastric emptying, accommodation, satiation and satiety have been recorded and transmitted to the statistician for data lock.
Who is eligible to participate?
- Obese subjects with BMI> 30 Kg/m2: Otherwise healthy individuals who are not currently on treatment for cardiac, pulmonary, gastrointestinal, hepatic, renal, hematological, neurological, endocrine (other than hyperglycemia not requiring medical therapy) and unstable psychiatric disease.
- Age: 18-70 years
- Gender: Men or women. Women of childbearing potential will have negative pregnancy test before initiation of medication.
- Weight >300 lbs which is the limit of safety for the SPECT scanner
- Concomitant use of appetite suppressants (i.e. caffeine based or diethylpropion) or orlistat (Xenical®)
- Uncontrolled hypertension (Blood pressure greater than 160/90 mmHg)
- Concentration of fasting glucose greater than 240 mg/dl
- Concentration of triglycerides greater than 400 mg/dl
- Type 1 Diabetes
- use of anti-diabetic drugs other than metformin,
- history of nephrolithiasis,
- recurrent major depression, presence or history of suicidal behaviour or ideation with intent to act, and current substantial depressive symptoms (Patient Health Questionnaire [PHQ-9]21 total score ≥10).
- Concomitant use of MAOI inhibitors (i.e. phenelzine, selegiline), serotonergic agents, and other centrally acting appetite suppressants
- Significant psychiatric dysfunction based upon screening with the Hospital Anxiety and Depression Scale [HADS] self-administered alcoholism screening test (SAAST, substance abuse) and the questionnaire on eating and weight patterns (binge eating disorders and bulimia). If such a dysfunction is identified by a HADS score ≥11 in any of the subscales or difficulties with substance or eating disorders, the participant will be excluded and given a referral letter to his/her primary care doctor for further appraisal and follow-up.
- End stage renal disease or liver cirrhosis
- Intake of medication that could interfere with the interpretation of the study or cause drug interaction (i.e. ketoconazole, erythromycin). Specifically, birth control pill, estrogen replacement therapy, and thyroxine replacement are permissible.