Studying the Effects of Phentermine on Eating Behavior

Study Overview
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Brief Summary
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The goal of this study is to determine whether one week of phentermine compared to placebo administration results in changes in food intake during a laboratory meal.

Detailed Description
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This study aims to explore whether short-term measures of eating behavior can be related to later, longer-term weight loss. In a double-blind, randomized fashion, participants will be asked to take study medication for three weeks: one week of phentermine and two weeks of placebo. At the end of the first and third weeks, participants will be asked to participate in a range of eating behavior studies. Following this three-week, double-blind phase, participants will be offered 6 months of open treatment for weight loss.

Official Title
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The Quantification of Ingestive Behavior

Conditions
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Obesity

Intervention / Treatment
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* Drug: Phentermine
* Drug: placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: BMI between 30-40kg/m2 Stable weight (+5 lbs) for a minimum of 3 months Systolic Blood Pressure <140mm Hg Diastolic Blood Pressure <90 mm Hg Pulse <95 beats per minute English language proficiency Exclusion Criteria: Previous unsuccessful trial of phentermine Prior adverse reaction to phentermine On any antidepressant medications,especially monoamine oxidase inhibitors(MAOI) History of neurological disorder (e.g. dementia) History of moderate or severe head injury Current or past history of coronary artery disease Current or past history of stroke or transient ischemic attack Current or past history of heart arrhythmias Current of past history of congestive heart failure Current or past history of peripheral artery disease Current or past history of liver disease Current or past history of kidney disease Uncontrolled diabetes mellitus (type I or II) Narrow-angle glaucoma Hypo- or hyper-thyroidism not adequately treated On medications (prescribed or OTC) known to affect appetite (e.g. diet pills), weight, or metabolism Current or past history (within the past 12 months) of major depression Current or past history (past 12 months) of alcohol or drug abuse or dependence Current or past history (lifetime) of amphetamine abuse or dependence Known history of learning disorder or developmental disability Current or past Attention Deficit Hyperactivity Disorder (ADHD) Pregnancy, planning to become pregnant, or lactation within the previous 6 months Waist circumference greater than 188cm Indwelling metallic object (e.g., pacemaker,pump), non-removable metal jewelry, medicinal patch or recent metallic ink tattoo Significant claustrophobia Current or past history of anorexia nervosa,bulimia nervosa (within the past 12 months) or binge eating disorder (within the previous 6 months)

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 60 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: 37.5 mg Phentermine daily for 7 days<br>In this arm, participants receive 37.5mg phentermine for one week followed by 2 weeks of placebo. Other names for phentermine: adipex ionamin | Drug: Phentermine<br>* After 7 days of phentermine 37.5 mg administration, food intake should be less than after 14 days of placebo.<br>* Other names: ionamin;|
| Placebo Comparator: Placebo (for phentermine 37.5mg)<br>In this arm, participants receive Placebo (for 37.5mg phentermine) for two weeks followed by phentermine 37.5mg for 7 days. | Drug: placebo<br>* Food intake as measured by a laboratory study should be greater after 7 days of placebo administration compared to seven days of phentermine administration.<br>* Other names: sugar pill;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Food Intake | The primary outcome measure is food intake assessed by laboratory meal study after one week of phentermine administration compared to one week of placebo administration. | one week |