Nurseweek/Healthweek | Fen-Phen may trigger heart disease

Mayo research suggests link between Fen-Phen and heart disease

posted 7-23-97

The drug combination "Fen-Phen," prescribed to 18 million Americans last year for weight loss, can trigger heart disease in otherwise healthy patients, according to a preliminary report to appear in the Aug. 28 New England Journal of Medicine.

Because of the potential public health threat, researchers from Minnesota’s Mayo Clinic will publish the unexpected finding before conducting follow-up studies. The report says that candidates for Fen-Phen therapy "should be informed about serious potential adverse effects, including pulmonary hypertension and valvular heart disease."

Fen-Phen is created by combining two drugs—fenfluramine, an appetite suppressant, and phentermine, a stimulant. Although both halves of the final product are FDA-approved, the FDA did not approve the combination, which physicians are prescribing. Philadelphia-based Wyeth-Ayerst Laboratories, which produces fenfluramine, has announced plans for a rigorous, prospective study in conjunction with the Mayo Clinic to examine the issue and test how potential biases, such as dosage, could influence findings. In a recent letter to prescribers, the drug maker warned against the "concomitant use of fenfluramine with other weight-loss agents."

The preliminary study documents the cases of 24 women who took the diet drug for six to 18 months. According to Heidi M. Connolly, MD, one of the co-authors of the report, all the patients experienced valvular heart disease, and five required open-heart surgery to repair deteriorated valves. Surgeons discovered that leaking valves regurgitated blood to the heart and were characterized by an unusual "glistened white appearance."

Researchers ruled out obesity as the cause of the damage. "Except for systemic hypertension, all the patients were thought to be free of cardiovascular disease at the onset of weight-reduction therapy," according to the report.

Connolly said that none of the 24 patients has died, but noted that cardiovascular diseases may diminish life expectancy.

The research evolved from routine clinical evaluations as physicians noticed a pattern among women admitted to the hospital for heart-related symptoms and their use of Fen-Phen. Physicians made no attempt to solicit cases or to cross-index files. According to the report, definitive statements about Fen-Phen’s effects cannot be made without a control group or case-control study.