Studying the Effects of Phentermine on Eating Behavior

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.

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)