Phentermine Mechanism of Action and Clinical Implications

Primary Mechanism and Physiologic Effects

• Phentermine acts as a potent substrate at the norepinephrine transporter, simultaneously promoting norepinephrine release while blocking its reuptake, according to the American Medical Association, as reported in JAMA 1, 2
• The drug reduces appetite and affects food intake via enhanced norepinephrine signaling in hypothalamic satiety centers, as described in JAMA 1, 2
• Phentermine may also increase resting energy expenditure, though appetite suppression appears to be the dominant mechanism, as noted in a medical guideline 3

Clinical Implications and Safety Considerations

• The noradrenergic mechanism explains phentermine's cardiovascular effects, such as increased heart rate and blood pressure, which require monitoring during therapy, as recommended by the Obesity Society, based on research published in Obesity Reviews and JAMA 1, 4
• The drug's amphetamine-like structure and mechanism confer Schedule IV controlled substance status due to potential for abuse and dependence, as classified by medical authorities, according to Obesity Reviews and Praxis Medical Insights 4, 5