For Release: March 15, 2000
Contact: Kimberly Lynch, ACCP
(847) 498-8341
[email protected]
INCREASED USE OF APPETITE SUPPRESSANTS LINKED TO INCREASED PULMONARY HYPERTENSION
The increased use of the appetite suppressant, fenfluramine, is strongly associated with the reported increase of pulmonary hypertension in the United States, according to a new study in CHEST, the peer-reviewed journal of the American College of Chest Physicians.
Researchers at 12 medical centers, to which patients diagnosed with pulmonary hypertension were referred, studied 579 patients to collect data to document patient exposure to commonly used medications, with special emphasis on anorexigens (appetite suppressants) and chemically related substances. The researchers developed a multicenter prospective surveillance study called the Surveillance of North American Pulmonary Hypertension (SNAP). Although European studies earlier linked anorexigens with primary pulmonary hypertension, SNAP was the first study in the U.S. to document an association between fenfluramine and primary pulmonary hypertension.
In April 1996, the U.S. Food and Drug Administration approved dexfenfluramine for extended use as an anorexigen in the United States (Europe restricted use of appetite suppressants to three months). At the same time, the use of fenfluramine and phentermine together (commonly referred to as "fen-phen") was gaining in popularity.
As it did, researchers noted, primary pulmonary hypertension cases began appearing.
Also, reported at that time were forms of heart-valve diseases associated with "fen- phen." The manufacturer's withdrawal of dexfenfluramine and fenfluramine from the worldwide market took place in September 1997. The SNAP study collected data on patients seen from September 1996 to December 1997.
Pulmonary hypertension is a relatively rare blood vessel disorder of the lung in which the pressure in the pulmonary artery rises above normal levels and can become life-threatening. When the disease occurs in the absence of a known cause, it is referred to as primary pulmonary hypertension (PPH). Secondary primary hypertension (SPH) means the cause has been established. Emphysema and bronchitis are common causes of SPH. Pulmonary hypertension historically has been chronic and incurable with a poor survival rate. According to the Pulmonary Hypertension Association, new treatments have extended the length of survival with some patients reportedly able to manage the disorder for up to 15 to 20 years. Although a new study on PPH mortality (also appearing in the March issue of CHEST) reports it is a "disease with a three-year survivorship in the absence of transplantation."
According to this new report, women die in much greater numbers than men, and blacks in much greater numbers than whites. The overall mortality for PPH is reported to be two persons per million for whites and seven persons per million for blacks.
In the SNAP study, 205 patients had PPH and 367 had SPH. Seven had pulmonary hypertension associated with HIV infection. More than 16 percent of those with PPH were using anorexigens compared with 11.4 percent for those with SPH using anorexigens, which was nevertheless considered surprisingly high by researchers.
More than 11 percent of those with PPH were using fenfluramines compared with 4.9 percent of those with SPH. Those in the PPH group were more likely to use fenfluramine for a longer period of time and more recently (in relation to onset of symptoms) than the SPH group.
Stuart Rich, M.D., FCCP, Section of Cardiology, Rush Medical College, and his colleagues concluded that: "The magnitude of the association with PPH, the increase of association with increasing duration of use, and the specificity for fenfluramines are consistent with previous studies indicating that fenfluramines are causally related to PPH. The high prevalence of anorexigen use inpatients with SPH," they added, "also raises the possibility that these drugs precipitate pulmonary hypertension in patients with underlying conditions associated with SPH."
The researchers said that the withdrawal of dexfenfluramine and fenfluramine from the market in 1997 also caused a major drop in the use of phentemine (the "phen" of fen-phen). "Fortunately," they added, "the exposure of large populations to long durations of use of the appetite suppressants did not have time to take place." That withdrawal, they opined, may well have aborted an incipient epidemic in the United States.
CHEST is published by the American College of Chest Physicians which represents 15,000 members who provide clinical, respiratory, and cardiothoracic patient care in the U.S. and throughout the world.
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Reporters may wish to contact Kimberly Lynch of the ACCP at (847) 498-8341 for a full copy of this article. She can also be reached by fax at (847) 498-5460 or by email at [email protected]. Dr. Rich can be reached by phone at (312) 563-2169 or by email at [email protected].
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