Americans frightened by the swine flu are snapping up two antiviral medicines that treat the virus, whether they have it or not.
New data show more than a quarter-million prescriptions for Tamiflu pills alone were filled at retail U.S pharmacies in the week ending last Friday. That's 34 times higher than the week before — as the regular influenza season wound down — and more than double the peak of last winter's flu season.
News accounts of the mysterious new type of influenza first surfaced about 10 days ago and have picked up ever since, as the number of deaths in the epicenter of Mexico has increased and as new cases have been reported in the U.S. and in many other countries.
The prescription figures from health care marketing consultants SDI of Plymouth Meeting, Pa., show that in the week ending last Friday, 257,459 prescriptions were filled at U.S. drugstores for Tamiflu, one of two medicines shown to work against swine flu.
The SDI data, released late Monday, also show prescriptions for a second antiviral drug effective against swine flu, Relenza, jumped to 13,710, 10 times higher than the prior week.
By comparison, there were barely 130 confirmed U.S. cases of swine flu reported as of Friday afternoon and less than 800 around the world confirmed by Saturday.
Both Tamiflu, made by the Roche Group, and Relenza, made by GlaxoSmithKline PLC, require a prescription.
Health authorities do not recommend taking the drugs as a preventive in people not exposed to someone infected with swine flu. However, both drugs have been shown to reduce chances of getting regular, seasonal influenza when a household member has the flu and relatives take it before onset of symptoms.
Unnecessary use of the two drugs could contribute to the virus becoming resistant to treatment in the future and, if shortages occur in pharmacies, could mean people who become sick can't get it right away. The medicine works best when taken within two days of the start of symptoms.
This past winter, Tamiflu turned out to be less effective against the seasonal flu strains then circulating. Sales dropped off, but picked up for Relenza.
The new SDI figures indicate many patients are convincing their doctor to write a prescription and then are filling it at a pharmacy.
Two older antiviral medicines that work against seasonal influenza but not against swine flu also saw significant, but much smaller, sales jumps last week.
Altogether, 287,481 prescriptions for the four antiviral drugs were filled last week, more than 13 times the number filled a week earlier.
During peak flu season, when sales of Tamiflu and Relenza crested in the last week of February, only 23,892 Relenza prescriptions and 108,424 for Tamiflu were filled.