Is dexfenfluramine effective in the treatment of obesity

Appraiser: Tom Hensing
Date: 8/30/96

Clinical scenario: A 41 year old woman who weighs 195 lbs (66 inches tall) has had difficulty with weight loss using diet and exercise. She is a non-smoker without hypertension or diabetes. She presents to clinic asking to be put on redox (dexfenfluramine).

Clinical bottom lines:

After six months of therapy with 15 mg bid dexfenfluramine significant weight loss and decrease in body mass index can be achieved. Treatment effect is lost within 6 months of stopping medication.

The evidence:

Prospective, double blind randomized trial of 60 men and women with moderate obesity
(age 18-64, average BMI greater than 34, 160% of ideal weight), enrolled in a weight loss
program, and with no comorbid disease; patients were randomized to 15 mg bid
dexfenfluramine or placebo, treated for six months and followed for six additional months.

  Dexfenfluramine Placebo p
6 months therapy      
Mean weight loss 9.7+/-1.1 kg 4.9+/-0.9 kg 0.002
Mean BMI 31.2+/-0.6 kg/m2 (34.8) 34.1+/-0.8 kg/m2 (35.6) 0.007
Greater than 10kg lost 50% 10.7%  
Changes in WHR 0.03 +/- 0.01 0.02+/-0.01 0.50
6 months follow-up      
Mean weight loss 6.0 +/- 1.6 kg 602+/-1.3 0.002



Comments:

*Well done randomized double blinded study with all patients accounted for.
*Minimal side effects with dexfenfluramine, including nausea, dry mouth and dizziness.
*Improvements were noted in serum triglyceride, HDL, and insulin levels.
*Not all patients randomized were included in the final analysis.
*Difficult to apply results to our patient population given high prevalence of comorbid disease, and lack of structured exercise and diet program.
*Cost: Dexfenfluramine $65.99/month, $792.00/year
*Significant weight regain after stopping drug indicating longer treatment is needed
* Little is known about the effect of long term treatment both on weight loss and complications of therapy (ie. primary pulmonary hypertension and necrologic damage).
*No data exists on improvement in mortality with drug therapy.

REFERENCES:

1. O'Connor, et al. Dexfenfluramine treatment of obesity: a double blind trial with post trial follow up. International Journal of Obesity 1995;19, 181-189.
2. Manson, et al. Body weight and mortality among women. New England Journal of Medicine September 14, 1995, 533. 677-685.