The Eli-Lilly Funded Phen-Pro Study
For years Dr. Anchors and others begged the Eli Lilly company, manufacturer of Prozac, to fund a study of phen-pro.
In January 1999 Eli Lilly finally funded a small study in which independent data collectors were sent to the offices of Drs. Michael Anchors in Maryland, Linda Brunson in Virginia and Dennis Padla in Michigan. The collectors collected the data on ALL patients on phentermine-Prozac and the data was analyzed by Keith Selander, an independent statistician.
The results, shown in the following graph, show that 117 patients on phentermine alone did not lose weight whereas 711 patients on phen-pro lost about 15% (average) of their total body weight in 9 months. This is far better than the results for Meridia or Xenical.
DETAILS
During 1992-1997 fenfluramine was often added to phentermine to enhance the anorexiant action of phentermine[1], but in 1997 fenfluramine was withdrawn from the U.S. market after being linked to cardiac valvulopathy.[2] Even in the heyday of the Òphen-fenÓ combination, a minority of physicians used the phentermine-fluoxetine combination instead of phen-fen[3], and the number of these physicians grew dramatically after fenfluramine was withdrawn. In spite of this, phentermine-fluoxetine combination received little attention from the media. There has been no published association between phentermine or fluoxetine and cardiac valvulopathy.[4]
In January 1999 the Eli Lilly Company, maker of fluoxetine, funded a retrospective trial of phentermine-fluoxetine, which we report here.
Figure
Percent weight loss versus time in obese patients on phentermine alone versus phentermine-fluoxetine combination
Methods
Professional data collectors were sent to the offices of Drs. Anchors, Padla and Brunson to collect data, using a standard protocol, from the charts of all obese patients (BMI > 30) treated with phentermine alone or the phentermine-fluoxetine combination. The doctors, practicing in different states without knowledge of each other during the time-period of the study, prescribed generic phentermine 30 mg with or without fluoxetine 20 mg per day. In addition, they recommended a low-calorie diet and exercise, with few specifics. The follow-up interval varied from every 2 weeks to 3 months. The data were analyzed by independent statistical consultant Keith Selander, and James Rochon MD of John Hopkins University provided valuable advice and oversight.
Results
117 patients on phentermine alone lost 3.7 + 6.6% (mean + SD) of their body weight, mostly within the first 6 weeks of therapy, and then regained their weight. 711 patients on phentermine-fluoxetine combination lost 11.6 + 9.6% of their weight with no noticeable tendency to regain; 20% of the cohort reached ideal body weight during the 18 months of the trial. There were no significant adverse events. Over 100 echocardiograms on the study subjects showed no evidence of cardiac valvulopathy.
Comment
Clinical experience suggests that the addition of fluoxetine, and some other SSRI drugs as well3, may enhance and extend the anorexiant action of phentermine. At a time when so many Americans are obese and so few effective anorexiants are available, a double-blind placebo-controlled trial of phentermine-fluoxetine is long overdue.
Michael Anchors, MD, PhD
Georgetown University School of Medicine
Washington DC
Dennis Padla, MD
St. Joseph MI
Linda Brunson, MD
Roanoke, VA
References
- Weintraub M. Long-term weight control: the National Heart, Lung, and Blood Institute funded multimodal intervention study [published erratum appears in Clin Pharmacol Ther 1992 Sep;52(3):323]. Clinical Pharmacology and Therapeutics, 1992 May, 51(5): 581-646.
- Connolly HM; Crary JL; McGoon MD; Hensrud DD; Edwards BS; Edwards WD; Schaff HV. Valvular heart disease associated with fenfluramine-phentermine [see comments] [published erratum appears in N Engl J Med 1997 Dec 11;337(24):1783]. New England Journal of Medicine, 1997 Aug 28, 337(9):581-8.
- Anchors M. Safer Than Phen-Fen. Prima Publishing, Rocklin, CA, 224 pages, 1997.
- Griffen L; Anchors M. The “phen-pro” diet drug combination is not associated with valvular heart disease [letter; comment]. Archives of Internal Medicine, 1998 Jun 8, 158(11):1278-9.