Fen-Phen The Drugs - Redux Overview Redux (dexfenfluramine hydrochloride capsules) is a drug that is the principal component of fenfluramine. Fenfluramine has been reported to be associated with the occurrence of serious regurgitant cardiac valvular disease, including disease of the mitral, aortic, and/or tricuspid valves. In one report, 24 patients who received combination therapy with fenfluramine and phentermine for the treatment of obesity were found to have regurgitant cardiac valvular disease; five of these patients required valvular surgery. The valves of these five patients were found to have a gross pathologic and/or histologic appearance resembling that seen in patients with alterations in serotonin metabolism. In these reports and other reported cases, fenfluramine was taken generally in combination with phentermine. However, there are some reports in which the valvular disease was seen in patients taking fenfluramine alone; there are also reports of valvular disease in patients taking dexfenfluramine alone. Primary pulmonary hypertension - a rare, frequently fatal disease of the lungs - has been found to occur with increased frequency in patients who have received dexfenfluramine. The safety and effectiveness of the combined use of fenfluramine and phentermine or dexfenfluramine, and phentermine in the treatment of obesity have not been established, and there is no approved use of these products together in the treatment of obesity. Dexfenfluramine is approved only as a single agent. The safety and effectiveness of dexfenfluramine beyond one year have not been determined at this time. Pharmacological Actions
In clinical trials, Redux treatment in conjunction with a reduced-calorie diet is associated with a reduction in appetite and may slow gastric emptying. These and other actions may contribute to the reduction in caloric consumption associated with Redux. In one clinical trial, Redux was shown to preferentially decrease carbohydrate consumption at meals and to manage carbohydrate craving between meals by decreasing the consumption of snack foods with a high carbohydrate content in patients who frequently snack on such foods. Contraindications Redux is contraindicated in patients with diagnosed pulmonary hypertension. Redux is contraindicated in patients receiving monoamine oxidase inhibitors. Redux is contraindicated in patients with hypersensitivity to dexfenfluramine, fenfluramine, or related compounds. Warnings Dexfenfluramine is an appetite suppressant, and appetite suppressants increase the risk of developing primary pulmonary hypertension, an often fatal disorder. A 2 year, international (5 country), case-control (epidemiological) study identified 95 primary pulmonary hypertension (PPH) cases; 30 of these were classified as having been exposed to appetite suppressants in the past, either to commercially available medications, pharmacist-compounded preparations, or unknown weight loss agents. Of the 30 cases, 18 had been exposed to appetite suppressants for longer than three months. In this study, the use of appetite suppressants for longer than three months was associated with an increase in risk of developing PPH (odds ration = 23.1, 95% confidence interval = 6.9-77.7). There was no significant increase in risk for persons who had used these agents for 3 months or less. In the general population, the yearly occurrence of PPH is estimated to be about 1-2 cases per 1,000,000 persons. Therefore, the case-control study estimated the risk associated with the long-term use of appetite suppressants to be about 23-46 cases per million persons. According to the case-control study, obesity alone (body mass index greater than or equal to 30 kg/m2) was also associated with an increase of about two-fold in the risk of developing PPH. PPH is a serious condition; the 4-year survival rate has been reported to be 55%. The initial symptom of pulmonary hypertension is generally dyspnea. Other initial symptoms include: angina pectoris, syncope, or lower extremity edema. Patients should be advised to report immediately any deterioration in exercise tolerance. Treatment should be discontinued in patients who develop new, unexplained symptoms of dyspnea, angina pectoris, syncope, or lower extremity edema. These patients should be evaluated for the etiology of these symptoms and the possible presence of pulmonary hypertension. If you have questions regarding your legal options or Fen-phen, please contact us.
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The action of Redux in treating obesity is primarily via decreased caloric intake associated with increased serotonin levels in brain synapses. Redux is a serotonin reuptake inhibitor and releasing agent. In vitro studies have confirmed the dual serotoninergic mechanism of the action of dexfenfluramine by demonstrating that the drug inhibits serotonin reuptake by axon terminals and causes the release of serotonin from synaptosomes. In animals, the reduced caloric intake and the loss in body weight elicited by dexfenfluramine is associated with release of serotonin from presynaptic axon terminals in the brain, inhibition of neuronal serotonin reuptake, and, therefore, an increase of serotonin receptor activation. This results in an enhancement of serotoninergic transmission induced by dexfenfluramine selectively suppressed appetite for carbohydrates which resulted in reduction of food consumption when the dietary carbohydrate to protein ratio was high. Unlike amphetamines and other serotonin-active agonists and antagonists, dexfenfluramine neither enhances nor suppresses dopamine-mediated neurotransmission.