Extended‐release fenfluramine: Patient acceptance and efficacy of evening dosing

We compared the patient acceptance and efficacy of 60 mg extended‐release fenfluramine and placebo before the evening meal in a 10‐week, double‐blind clinical trial. All 51 participants were 130% to 180% of ideal body weight. They received instruction in diet and behavior modification for 2 wk before the beginning of and during the medication period. Mean weight loss was 5.9 kg (8.0 ± 4.6% of initial weight) in the fenfluramine group and 3.3 kg (5.5 ± 3.5%) in the placebo group. Fenfluramine‐treated participants reported lower hunger ratings and greater fullness in the target supper‐to‐bedtime period than participants receiving placebo. Both groups reported dry mouth, dizziness, drowsiness, fatigue, and diarrhea. Although the fenfluramine group reported more complaints, these diminished to less than half after 2 wk of treatment. Four of the fenfluramine and three of the placebo group dropped out for drug‐related reasons. In all, 10 fenfluramine and 8 placebo participants dropped out. Fenfluramine participants had a higher benefit score with no difference in risk scores. The fenfluramine group's global evaluation was better than that of the placebo group. Participants viewed the study and the dosing regimen positively but had negative ideas about anorexiants in general. Extended‐release fenfluramine taken in the evening was well tolerated and maintained its efficacy as measured by standard and novel techniques. Clinical Pharmacology and Therapeutics (1983) 33, 621–627; doi: 10.1038/clpt.1983.84