Long-term pharmacologic treatment of morbid obesity in a community practice

To determine the safety, efficacy, and metabolic changes in patients with morbid obesity treated with d,l-fenfluramine and phentermine in an open-label trial.

In patients with a body mass index (BMI) =40.0 kg/m 2 (N = 298) who sought assistance at a private medical practice for treatment of obesity, 60 mg of d,l-fenfluramine and 15 to 30 mg of phentermine resin were administered daily in an open-label trial, without placebo controls, for up to 24 months. The setting was a community-based private practice. Study subjects were given instructions for a 1,200 to 1,400 kcal/day diet, exercise, and behavior modification. Follow-up included a monthly medical visit, behavior modification group attendance, quarterly laboratory evaluation, and electrocardiographic monitoring.

BMI decreased from 45.8 kg/m2 to 37.4 kg/m2 (P<0.0001) in those who completed 12 months of treatment and to 38.2 kg/m2 (P<0.0001) in those who continued the protocol for 24 months. Statistically significant decreases in fasting blood glucose, total and high-density lipoprotein cholesterol, triglycerides, systolic and diastolic blood pressures, and fasting insulin concentrations were noted. The dropout rate was 42.3% at 12 months and 69.8% at 24 months. The most common reason given for discontinuing participation in the study was "success" with the program (mean BMI loss of 7.8 kg/m2). Five patients discontinued treatment because of side effects. No laboratory or electrocardiographic abnormalities were noted that could be attributed to the medications. No statistically significant regain of weight occurred in those who completed 12 or 24 months of treatment.

In this study, treatment of morbid obesity with d,l-fenfluramine and phentermine was safe and efficacious in promoting and maintaining weight loss. Moreover, statistically significant changes were noted in metabolic variables associated with risk of heart disease. Future efforts must focus on methods to improve long-term compliance.