Journal of Obesity & Metabolic Syndrome



Korean J Obes 2005; 14(3): 155-162

Published online July 1, 2005

Copyright © Korean Society for the Study of Obesity.

Double-blind, Parallel-group, Placebo-controlled Multi-center Clinical Trial for Evaluating the Efficacy and Safety of Phentermine Hydrochloride in Obese Patients

Chang Jin Choi, Kyung-Soo Kim, Sung Rae Kim¹, Jae Heon Kang², Hye Soon Park³

Department of Family Medicine, Department of Internal Medicine¹, College of Medicine, The Catholic University of Korea, Seoul;
Korea, Department of Family Medicine, Seoul Paik Hospital, College of Medicine, Inje University², Seoul, Korea;
Department of Family Medicine, Asan Medical Center, Ulsan University College of Medicine³, Seoul, Korea


Background: Phentermine is a sympathomimetic amine used as an appetite suppressant for short term therapy. The aim of this study is to evaluate the efficacy and safety of phentermine in Korean obese patients.
Method: This study was a 12-week, double blind, multi-center placebo-controlled clinical trial followed by a 2 week screening period. Patients with a body mass index of either greater than 30 kg/㎡ or between 27 and 30 kg/㎡ with controlled hypertension, diabetes and hyperlipidemia were considered eligible. Participants of 119 obese patients were randomized either to phentermine (59 patients) or placebo (60 patients) at 4 participating centers.
Results: After 12 weeks of treatment, mean weight reduction at 12 week was 7.94 ± 7.31 kg among phentermine group and 0.91 ± 5.88 kg among placebo group (P < 0.001). In phentermine group, 73.6% of patients lost 5% or more of their initial body weight in contrast to 15.1% in placebo group. Phentermine-induced weight reduction was not associated with any significant improvements in serum level of fasting glucose and lipid profile compared to placebo. Changes in blood pressure were not different among the two groups, however, pulse rate was significantly elevated in phentermine group. The drop out rate was 11.7% for both groups. Among the reported adverse events in phentermine group, dry mouth (22.0%) was significantly higher compared with placebo group (5.0%) (P < 0.001).
Conclusions: Phentermine is well tolerated and is considered to be an effective short term therapy for managing obesity among the Korean population.

Keywords: Obesity, Weight loss, Phentermine, Efficacy, Safety, Double-blind