New research showing that phenylpropanolamine (PPA), an ingredient commonly found in cold remedies and appetite suppressants, is linked to an increased risk of stroke has prompted a public health warning from the US Food and Drug Administration, and US manufacturers and distributors are pulling products containing PPA from the market.
The actions came in response to a five-year study based at Yale University, the results of which indicate that PPA is an independent risk factor for hemorrhagic stroke in women. Because of the public health implications of the study, the New England Journal of Medicine released the results prior to the publication date of December 21. The study was prompted by case reports linking the use of products containing PPA, a synthetic sympathomimetic amine, to hemorrhagic stroke, often after the first use.
Kernan et al recruited 702 male and female patients, 18 to 49 years of age, who had a subarachnoid or intracerebral hemorrhage within 30 days before enrollment and the absence of a previously diagnosed brain lesion; these were matched with 1,376 control subjects. Women who had used appetite suppressants containing PPA were up to16 times more likely to have a hemorrhagic stroke as women who hadn't, and first time users were three times as likely to have a stroke. The findings prompted the FDA to issue a public health warning, and the agency is taking steps to remove PPA from all drug products and has requested that all drug companies discontinue marketing products containing the substance.
In the UK — where levels of PPA in cold remedies are generally lower than those allowed in the US — the Department of Health has ordered an urgent enquiry into the use of PPA.