PHENYLPROPANOLAMINE USE WITH ORAL CONTRACEPTIVES OR PROSTAGLANDIN INHIBITORS
PHENYLPROPANOLAMINE USE WITH ORAL CONTRACEPTIVES OR PROSTAGLANDIN INHIBITORS may be confounding variables in evaluating the OTC weight loss ingredient's blood pressure effects, FDA medical officer Philip Dern, MD, observed April 11 during a meeting with Ciba-Geigy representatives. Noting that "there's a significant case of hypertension when there is a rechallenge with indomethacin," Dern said: "Prostaglandin inhibitors such as aspirin, indomethacin and others . . . and oral contraceptives are two variables that might very well condition severe hypertension." FDA met with Ciba-Geigy to discuss development of a phenylpropanolamine dose response protocol. The agency indicated at a feedback meeting with Thompson Medical and Robins in December that it would like industry to conduct a phenylpropanolamine pilot study to determine the drug's safety margin ("The Pink Sheet" Dec. 5, T&G-1). FDA Cardio-Renal Div. Acting Director Raymond Lipicky, MD, described "one scenario" of what could be found with a dose-response study. "Let us say, for example, that what you have to do in order to get blood pressure to raise really dramatically was to give 10 grams of phenylpropanolamine and that only happened on the first dose," Lipicky said. "By the time you gave the second dose you'd have to give 100 grams and by the time you gave the third dose you'd have to give 10,000 grams." If you had that kind of information, he said, you could say the hemodynamics of phenylpropanolamine are not very important "except in gross overdose." Lipicky remarked that right now we know the drug has hemodynamic activity but we don't know "what the next increment of dose will do." Ciba-Geigy consultant Thomas Garvey, MD, said he would like to analyze the data set of spontaneous adverse reaction reports to consider factors such as sex and concommitant use of other drugs. He also cited a survey by the Center for Science in the Public Interest which found 17 respondents had strokes or seizures while taking phenylpropanolamine. Garvey remarked that "eleven of the 17 patients" were also taking caffeine and that "there is evidence that probably five more of the remaining six were also taking caffeine." Noting that the survey does not constitute a study and is uncontrolled, Garvey said it nevertheless raises questions that "need to be addressed." Ciba-Geigy also presented the results of two market research studies it has conducted at shopping malls in three cities. Ciba-Consumer Pharmaceuticals President Jeff Lyle reported that of 459 female appetite suppressant users interviewed "only about 11%" fall within the range of what would be considered seriously overweight. He said 76% of users are 21 to 30 pounds over the ideal weight listed in the 1983 Metropolitan Life Tables. Lyle also noted that 89% of the users are 18 to 44 years old and of that population 11.9% are hypertensive.
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