Phenylpropanolamine may increase risk of haemorrhagic stroke, according to
United States researchers. The decongestant is found in many over-the-counter
(OTC) cold, cough and hay fever products.
Researchers from the Yale university school of medicine presented the results
of a five-year study examining the effect of phenylpropanolamine on the risk
of haemorrhagic stroke to the US Food and Drug Administration (FDA) on October
19.
The study involved 702 patients who had had subarachnoid or intracerebral haemorrhage
and 1,376 matched controls. Trial participants were classified as having exposure
to phenylpropanolamine if they reported use within three days of the stroke
or the corresponding date for control subjects. All were aged between 18 and
49 years with no prior history of stroke.
The adjusted odds ratio for association between haemorrhagic stroke and any
phenylpropanolamine use within three days was 1.49. The odds ratio for association
between haemorrhagic stroke and use of phenylpropanolamine in cough and cold
remedies was 1.23 and 15.92 in appetite suppressants (an additional indication
in the US). The odds ratios were increased for women.
The FDA has yet to make a decision over the future of phenylpropanolamine.
The Proprietary Association of Great Britain (PAGB) emphasised in a press statement
that the maximum approved daily OTC dose of phenylpropanolamine was higher in
the US — 150mg compared with 100mg — than in the United Kingdom. In
addition, phenylprop-anolamine was only used in cough and cold preparations
and not in appetite suppressants. The PAGB says that millions of doses have
been taken safely and effectively in the UK for the relief of cold symptoms
and that: “There is no reliable evidence of a causal link between phenylpropanolamine
and stroke if the product is used at doses approved in the UK according to the
label instructions.” However, overdose of phenylpropanolamine can increase
blood pressure, which is known to increase the risk of stroke, it adds.
A spokeswoman for the Medicines Control Agency told The Journal on October 24
that the MCA was aware of the advice given to the FDA.
The Committee on Safety of Medicines would review the evidence and make recommendations
to the MCA, she added.