Although evidence-based medicine has caught on among physicians, it seems that regulatory agencies persist in generating hysteria-based blanket recommendations.
Donald Farquhar1 wrote a clinical update for CMAJ on a case–control study showing that, mainly when it is used repeatedly for appetite suppresion, phenylpropanolamine is associated with increased risk of hemorrhagic stroke primarily in women who smoke cigarettes and are black, hypertensive and less well educated.2 This population also seems to be at some risk even at first use of phenylpropanolamine- containing cough or cold remedies. On this basis the US Food and Drug Administration and Health Canada announced they were taking steps to remove phenylpropanolamine from all drug products and requested that all drug companies stop marketing products containing phenylpropanolamine.
Why? How many millions of patients find relief from using these medications each year, and what is their risk of stroke? The risk is not distributed evenly, because among men there was no increased risk of hemorrhagic stroke with use of phenylpropanolamine- containing products.2
What is the number needed to harm? Since 1969, only 60 cases of hemorrhagic stroke associated with the use of products containing phenylpropanolamine have been reported to the US Food and Drug Administration, or about 2 reported strokes per year.2
This isn't the first time good medicines have been killed because regulatory agencies have overreacted. Cisapride was removed from the market after the deaths of fewer than a dozen people with identifiable risk factors. However, these agencies are somewhat inconsistent: dozens of men have accepted the well-publicized risk of death associated with use of sildenafil and died, yet this drug remains on the market.
We place appropriate warning signs concerning the risk of stroke on cigarette packages. Why not do the same with medications? When risk factors for serious harm become known they should be placed in bold type on the drug packaging and made well known to health care workers. Products containing phenylpropanolamine should probably be placed behind the counter so pharmacists can advise those patients identifiably at increased risk to use other products; they shouldn't be banned from the marketplace.