|
"PHEN/FEN" AND VALVULAR HEART DISEASE
July 8, 1997
QUESTIONS AND ANSWERS
1. WHAT IS "PHEN/FEN" ?
Phentermine ("phen") and fenfluramine ("fen") are prescription medications approved by the FDA as single medicines for short-term (a few weeks) use as appetite suppressants in the management of obesity. Some physicians have prescribed them recently to be used in combination with each other and to be used for extended periods of time in weight loss programs. Such use of the products is called "off label" because there have been no studies presented to the FDA to demonstrate either the effectiveness or safety of the two drugs taken together or for longer periods of time (greater than a few weeks).
"Phen" is short for phentermine, an amphetamine-like drug marketed under various trade names such as Ionamin® and Fastin®, as well as several generic forms of phentermine. It is approved for short-term use as an appetite suppressant.
"Fen" is short for fenfluramine, a drug affecting serotonin, marketed as Pondimin®. It is approved for short-term use as an appetite suppressant.
2. WHAT IS VALVULAR HEART DISEASE?
There are four major valves controlling the flow of blood into, out of, and between the four chambers of the heart. Several disease processes, including infection and toxicity, may damage the valves, causing them to malfunction, and may produce severe heart and/or lung disease.
3. WHAT IS THE RELATIONSHIP OF "PHEN/FEN" TO HEART DISEASE?
Recently, the FDA has received reports of confirmed valvular heart disease in the United States in at least 33 women between ages 35 and 72 who had taken the drug combination for time periods ranging between 1 and greater than 16 months (average 9.5 months). A direct causal relationship between the use of the drugs and the valve disease has not been established; however, the occurrence of a severe and usually rare disease in an otherwise healthy population of young obese women is a matter of serious public health concern. It is not known at present how the damage to the heart valves develops: whether it is due to either phentermine or fenfluramine alone, to the combination of products, or to other factors.
4. WHAT ARE THE SIGNS OF VALVULAR HEART DISEASE?
The occurrence of a new heart murmur (abnormal sound as the blood flows over a valve) is usually the first indication of the development of valvular heart disease. Abnormal valve function may then be evaluated by a painless, non-invasive test called echocardiography, usually performed by a cardiologist. More severe symptoms of the disease include shortness of breath, loss of tolerance to physical activity, and fluid retention in the legs and lungs.
5. IS THE VALVE DISEASE REVERSIBLE?
Presently, good data are not available to answer this question.
6. HOW IS VALVULAR DISEASE TREATED?
In some instances, medication can control the heart failure associated with valvular damage. In others, surgery to replace the valves with artificial valves may be necessary.
7. IS VALVULAR HEART DISEASE RELATED TO PRIMARY PULMONARY HYPERTENSION?
Primary pulmonary hypertension is a disease of the heart and lungs caused by narrowing of blood vessels in the lungs. It has been reported to occur in about 1 in 25,000 people using appetite suppressants for more than 3 months. This disorder results in death in about 40% of affected individuals within 4 years. Primary pulmonary hypertension may also occur in association with valvular heart disease. More research is needed to determine if there is some relationship between the disease of the heart valves and the primary pulmonary hypertension also seen in certain patients who use these appetite suppressants.
8. SHOULD I STOP TAKING "PHEN/FEN" RIGHT NOW?
You should discuss with your health care provider what is the best course of action for your individual case.
9. WHAT DRUGS CAN BE USED IN PLACE OF PHEN/FEN?
You need to discuss with your health care provider whether alternative approaches to appetite suppression and weight control would be appropriate for your individual case. No currently available weight-loss drugs have been studied adequately in combinations to permit a recommendation by FDA for combined use. None of the currently available weight-loss drugs except dexfenfluramine has been studied for more than a few weeks use.
10. IS THIS JUST A DISEASE OF WOMEN?
To date, all 33 cases of which FDA is aware are women. However, there is no reason at present to believe that men could not also be affected. Most of the use of these products is in women, so what we are presently seeing could be only a reflection of the usage patterns of the products. FDA advises that male and female patients and their health care professionals should all be aware of this information; FDA encourages reporting to FDA or the manufacturers any case of valvular problems in male or female patients suspected of being associated with the use of these products.
Back to Phenfen Public Health Advisory
Date created: July 8, 1997; last update: July 7, 2005 |
