Fenfluramine incidence

In a summary of the human abuse literature on anorectic phenylethylamines, Griffiths et al. (1979) found there was a good correlation between the results of self-administration studies in animals and information about the subjective effects and abuse in man. Specifically, amphetamine, diethyl-propion, and phenmetrazine have been associated with numerous clinical case reports involving abuse, and these three compounds as well as benz-phetamine and /-ephedrine have shown similar subjective effects in drug abuser populations (Griffiths et al. 1979). In addition, fenfluramine was associated with low incidence of abuse in humans and did not maintain self-injection responding in animals. Chlorphentermine was similarly associated with low incidence of abuse in man, but did not maintain selfinjection uniformly in animals (Griffiths et al. 1979). 

It is now believed that physical activity has a more positive role in reducing fat in an obese person. Drugs used for obesity, fenfluramine and dextrofenfluramine, were licensed and later withdrawn from the market because of the incidence of pulmonary hypotension and heart valve defects in patients. The drugs, that are under development are leptin, cholecystokinin promoters, and troglitazone. At present, there are no safe drugs that are effective in the treatment of obesity. All one can usefully say to the obese patient is, stick to the diet, keep jogging, and seek medical advice. 

A 46-year-old woman took fenfluramine for 5 months without incident. Some time later she restarted therapy and after 2 months developed a hemoglobin concentration of 5.1 g/dl, a reticulocyte count of 8.6%, a white cell count of 17.1 x 10 /1, and a positive direct Coombs test, with IgG rhesus antibodies (anti-e and anti-nl). Fenfluramine was withdrawn and the Coombs test became negative and the patient recovered after prednisolone infusion. 

The principal side effects of phentermine are insomnia, restlessness, and euphoria. Some patients rapidly develop toleranee to this agent, resulting in discontinuation of therapy. The combination of phentermine with fenfluramine or dexfenfluramine was as-soeiated with inereased incidences of both primary pulmonary hypertension (PPH) and ear-diae valvulopathy, but it is unlikely that phentermine alone causes these same problems. Phentermine, nonetheless, contains a warning label listing PPH and cardiac valve lesions as possible adverse events. 

This is a well established and, on the whole, an advantageous rather than an adverse reaction, but it would be prudent to check on the extent of the response if fenfluramine is added or withdrawn from the treatment being received by diabetics. However, note that fenfluramine was generally withdrawn in 1997 because its use was found to be associated with a high incidence of abnormal echocardiograms indicating abnormal functioning of heart valves. 

Note that dexfenfluramine and fenfluramine have generally been withdrawn because their use was found to be associated with a high incidence of abnormal echocardiograms indicating abnormal functioning of heart valves. 

Four dosage schedules of fenfluramine and placebo were compared for effectiveness and tolerance in a double-blind study (18 ). One or more side effects were reported by 113 of the 231 (48.9%) patients treated with fenfluramine and by 21 of the 76 (27.6%) treated with placebo. Of the 158 side effects reported during fenfluramine treatment, the investigators considered 78 to be probably drug-related. A significantly greater incidence of side effects with fenfluramine oc-... 

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