Phenylpropanolamine, stroke and hypertension

The US Food and Drug Administration has issued a warning about the danger of phenylpropanolamine (PPA), a decongestant and appetite suppressant that occurs in various over-the-counter and prescription medications, after a report by researchers at Yale University revealed a link between exposure to PPA and strokes in women.¹ For the last 20 years, one of the research interests of the Hypertension Group at the Montreal Research Institute has been patients with pseudopheochromocytoma, paroxysmal hypertension in the absence of pheochromocytoma.² Among many patients referred for this condition were 2 who had experienced hypertensive episodes that were evidently induced by PPA. This spurred me to write an article warning health care professionals about adverse reactions to PPA.³ It would have been desirable for Health Canada to have reacted to this warning at least as quickly as the 2 drug companies who responded to my article. Pennwalt Inc. put emphasis on its slow- release form of PPA, which was supposedly devoid of this effect, and asked me for a retraction.⁴ Thompson Medical Co. Ltd. tried to defend its marketing of another supposedly innocent PPA isomer.⁵ I reluctantly wrote a retraction, and I had to admit that fewer hypertension-producing isomers of PPA may be used in North America than in Europe and Australia.⁶ At that time, I was not aware of further studies indicating that adverse reactions had also been associated with slow-release formulations and with isomers of PPA.⁷ The present FDA warning¹ and various drugstore announcements of the withdrawal of PPA⁸ do not make a distinction between different PPA formulations either. It is conceivable that a more proactive response by Health Canada could have prevented the wide use of this potentially dangerous drug for the last 12 years.

Signature

Otto Kuchel
Emeritus Professor Clinical Research Institute Université de Montréal Montreal, Que.