ACUTE ADMINISTRATION OF PHENYLPROPANOLAMINE FAILS TO AFFECT RESTING ENERGY-EXPENDITURE IN MEN OF NORMAL-WEIGHT

Studies have consistently found that dieters using over-the-counter we ight control products containing phenylpropanolamine (PPA) are more su ccessful at losing weight than those who do not, To explore the possib ility that drug-induced metabolic changes contribute to weight loss as sociated with this compound, this study investigated the effects of PP A on resting metabolic rate in 20 healthy men of normal weight between the ages of 18 and 29, After the arrival of the subjects to the labor atory, blood pressure was taken and resting energy expenditure (REE) a nd respiratory quotient (RQ) were assessed for 20 minutes (Baseline) v ia indirect calorimetry, Half of the subjects were then given 75 mg of immediate-release PPA (administered orally via a gelatin capsule), wh ile the other half received placebo, Immediately after drug administra tion, metabolic rate was measured for an additional 95 minutes (During Drug), After this assessment, blood pressure was again measured, Alth ough significant increases in both systolic and diastolic blood pressu re were observed after PPA administration, the drug had no effect on R EE or RQ, These results, consistent with that previously reported in m ildly overweight women, further establish that it is unlikely that dru g-induced metabolic changes contribute to PPA-induced weight loss in h umans.