The Nutri/ System Weight Loss Centers have rankled the makers of Prozac by promoting a combination of the anti-depressant and another drug as a diet aid.
Eli Lilly & Co. sent a letter to Nutri/System this week warning that the pharmaceutical giant does not endorse the Prozac and phentermine blend, or “phen-pro,” for weight loss.
The chain is using Prozac to replace fenfluramine, the half of the popular “fen-phen” diet cocktail that was recalled earlier this month at federal regulators’ request due to concerns that it damaged heart valves.
“Your advertising campaign creates potential public health issues and could mislead consumers,” officials of Indianapolis-based Lilly rote to the national weight-loss company based in Horsham, Pa., near Philadelphia.
Lilly officials noted that the U.S. Food and Drug Administration has not authorized Prozac for weight control, and said Nutri/System’s commercial references to the anti-depressant violate trademark law.
Lilly sent the letter to Joseph DiBartolomeo, Nutri/System’s vice president for scientific affairs, on Monday after he touted phen-pro on ABC’s “Good Morning America” last week.
A Lilly spokesman said Friday the company had no further comment.
Nutri/System has been promoting phen-pro since pulling the fenfluramine and the related drug dexfenfluramine from its 450 centers earlier this month.
The diet chain said its combination of the appetite suppressant phentermine and Prozac, dubbed “phen-pro,” is safe and that Lilly’s own researchers have found evidence that Prozac can treat obesity.
“It appears to be as effective as fen-phen, without the risk,” DiBartolomeo said Friday.
Last week, the FDA urged millions of dieters to immediately stop taking Redux, also known as dexfenfluramine, and Pondimin, also known as fenfluramine, after uncovering evidence they could seriously damage patients’ hearts.
Weeks earlier, Nutri/System dropped fen-phen as an option for its clients.
Some doctors have balked at the idea of phen-pro, saying it has not been adequately tested. While Prozac and phentermine may be safe when used alone, the combination has never been subjected to a standard clinical trial that compares results on phen-pro users and a controll group taking placebos.
DiBartolomeo defended the treatment, citing the work of Dr. Michael Anchors, a Georgetown University professor and author of a book on phen-pro who has prescribed it to 650 patients over two years.
Anchors found that only 10 failed to lose weight, while eight other patients suffered severe side effects, including nausea, insomnia and heart palpitations.
Three diabetics saw increased blood sugar levels.
DiBartolomeo also referred to Lilly’s own previous research on the weight loss effects of Prozac alone. It found that weight loss appeared to be a common side effect of Prozac and said use of the drug “may be a potentially useful strategy” in treating obesity.
That research did not examine the phen-pro combination. DiBartolomeo said he would like to see Lilly do a clinical trial on phen-pro.