RFO Program
from the University of California, Los Angeles
On September 13, 1997, the serotonergic drugs, fenfluramine (Pondimin) and dexfenfluramine (Redux) were voluntarily withdrawn by the manufacturer, Wyeth-Ayerst, because of a possible association with valvular heart disease in some patients who had received high doses for long periods of time. There is no proof of cause-and-effect, and the matter may only be settled with further research.
At the center we have consistently employed far lower doses of medications than usual, frequent readjustment of doses, meticulous preventative care and careful monitoring with electrocardiograms and examinations. We have experienced over one thousand patients years of fenfluramine/phentermine therapy and have had no signs or symptoms or an abnormal echocardiogram in any patients suggestive of either primary pulmonary hypertension or valvular heart disease.
In contrast to the serotonergic drugs, the noradrenergic drugs (phentermine, diethylpropion, mazindol) have never been associated with either primary pulmonary hypertension or valvular heart disease. A common misconception is that the combination of fenfluramine and phentermine (Fen/Phen) is better than phentermine alone. This is not the case. In the original study by Dr. Weintraub, he showed that the combination utilizing low doses of these two medications was "as good as" either medication alone in higher doses and with fewer side effects, such as insomnia, constipation or restlessness. We continue to prescribe the noradrenergic drugs when indicated, and if annoying side effects occur plan to add another safe medication to counteract them.
The newest FDA approved appetite-suppressant drug is sibutramine (Meridia). Meridia has a similar mechanism as the combination phentermine/fenfluramine; it inhibits the reuptake of both serotonin and noradrenaline, thus prolonging the effect of these neurotransmitters in the brain centers, which regulate appetite. In 6000 patients carefully studied before its release, Meridia has not been associated with any heart or lung damage. The main side effects, seen in a small number of patients, are headache, dry mouth, constipation and insomnia. Meridia may cause a significant increase in blood pressure, so blood pressure must be monitored regularly. At the center, we are carefully titrating Meridia, starting with a minimal dose, to avoid side effects and achieve maximal weight loss.
With a variety of appetite-suppressant drugs to choose from and with frequent readjustment of medication, we are generally successful in finding a combination for each person, which results in steady weight loss, and no side effects other than dry mouth. Vital signs are recorded weekly and laboratory determinations and electrocardiograms are obtained serially.
After assessing any possible risk factors and with each patient's approval, small doses of appetite suppressant drugs may be added to the VLCD or LCD., standard low calorie diets described previously.