2009 年 40 巻 1 号 p. 17-21
Phenylpropanolamine (PPA) is a sympathomimetic used as a cold remedy for the relief of nasal congestion. PPA was also used as an appetite suppressant in several countries (e.g., US and Australia). Since 1969, there have been case reports and spontaneous reports on the association between PPA and hemorrhagic stroke among young people. The US Food and Drug Administration (FDA) and manufacturers of products containing PPA agreed to collaborate to resolve the issue by implementing a case-control study. As a result, PPA was shown to increase the risk of hemorrhagic stroke in women particularly when used as an appetite suppressant. The US FDA asked the firms to commit voluntary withdrawal of all products containing PPA in November 2000. In Japan and Korea, following the label change of the drug containing PPA, PPA was eventually withdrawn during the period 2001-2003. As the incidence of hemorrhagic stroke is high in eastern Asia, the association between hemorrhagic stroke and PPA may differ from that in the US. The Korean FDA then implemented a case-control study similar to that conducted in the US. The results suggested that PPA contained in cold remedies increases the risk of hemorrhagic stroke regardless of age and dose of PPA. Unfortunately, such a study was not implemented in Japan. In general, it is difficult for the government to take appropriate action regarding the safety concerns of a drug using only limited information. It is therefore highly desirable to attempt to verify the action by implementing scientific studies.