NEW YORK, Mar 13 (Reuters Health) -- Obesity drugs pulled from the market
due to reports of heart complications may also have played a role in the rise in
the number of cases of a rare lung disorder in the US, researchers suggest.
Dexfenfluramine and fenfluramine are anti-obesity drugs withdrawn from the
market by the Food and Drug Administration in 1997 due to their potential to
cause heart problems. These drugs have also been linked to a serious lung
disorder, primary pulmonary hypertension. This is a rare, life-threatening
disease of unknown cause in which the blood pressure in large arteries in the
lung is abnormally high, leading to problems with breathing and heart function.
To save their lives, patients may need to have a heart-lung transplant.
A study published in the journal Chest found that death rates due to primary
pulmonary hypertension in the US have increased since 1979, especially among
black women. The authors say that anorexigens, a class of drug of which
fenfluramines are a member, may be responsible for "some portion of this
increase."
In the study, Dr. David E. Lilienfeld of Bristol-Myers Squibb in Princeton,
New Jersey, and colleagues studied primary pulmonary hypertension death rates in
the US between 1979 and 1996.
The investigators found that deaths due to the disorder have "increased
notably" since 1979. Among adults, mortality from primary pulmonary hypertension
was higher in blacks than in whites and in women than in men. Black women had
the highest mortality rate, at nine deaths per one million people, and they also
have shown the steepest rise in death rates from the disease during this period.
Lilienfeld's team also notes that their data suggests "that the disease may
be more common in the elderly than has been previously thought."
In a second study published in Chest, Dr. Stuart Rich of the
Rush-Presbyterian-St. Luke's Medical Center in Chicago, Illinois, and other
members of the Surveillance of North American Pulmonary Hypertension research
team collected drug information from 579 patients with pulmonary hypertension
treated at 12 large referral centers in North America from 1996 to 1997.
Of these, 205 patients had primary pulmonary hypertension. The remaining 374
patients were classified as having secondary pulmonary hypertension, where the
cause of the disease is known and is usually due to emphysema, bronchitis, or
other underlying disease.
The team found that over 11% of patients with primary pulmonary hypertension
had used fenfluramines, compared to less than 5% of patients with secondary
pulmonary hypertension.
Patients who had used fenfluramines longer than 6 months had an increased
risk of developing primary pulmonary hypertension. The risk increased with
longer duration of use compared with shorter-term usage and was higher in recent
users.
"This study supports the findings of previous reports that fenfluramines are
risk factors for primary pulmonary hypertension," Rich and co-authors conclude.
The quick withdrawal of fenfluramines "from the United States market may
well have aborted an incipient epidemic (of pulmonary hypertension) in the
United States," they suggest.
