TORONTO -- Despite cautions to the contrary, news media reporting of avian flu and concerns about pandemic spread were followed by hoarding of the antiviral medication Tamiflu (Oseltamivir) by Americans according to a collaborative study by the Centers for Disease Control and Prevention (CDC) and Medco Health Solutions, Inc. The findings from the first national study of personal Tamiflu stockpiling were presented at the annual meeting of the Infectious Diseases Society of America (IDSA).
The research reveals that the number of prescriptions filled for Tamiflu jumped more than 300 percent from 2004 to 2005 during the fall months when there was little or no influenza activity in the United States. Tamiflu prescriptions filled during September and October rose to 133.6 per 100,000 insured Medco enrollees in 2005, up from 27.3 prescriptions per 100,000 enrollees during that same time period in 2004. When extrapolated to the U.S. population, that's 305,000 more Tamiflu prescriptions filled in
2005 than would have been expected based on 2004 prescribing rates. The largest proportion of Tamiflu prescriptions filled in 2005 was by those categorized as the healthiest patients.
The investigation also found that the number of prescriptions written per doctor increased substantially. Since Tamiflu is recommended for use within 48 hours after flu symptoms appear and virtually no cases of the illness had been reported during this time period, it is likely that the medication was not prescribed to treat the flu; instead it was probably stockpiled by patients over fears of a possible bird flu outbreak. The rise in Tamiflu prescriptions also corresponded closely to increased media coverage of avian flu.
"The correlation between the heightened U.S. media coverage around Tamiflu and the prescription activity for the drug between September and November in 2005 is uncanny -- nearly a five-fold increase in prescribing rates among physicians occurred over this typically low influenza time period," said Dr. Robert Epstein, Medco's chief medical officer and co-author of the presentation.
Further findings of the study showed that among age groups, the highest prescription rates in 2005 were for persons aged 50-64 years, despite the fact that those 65 years and older experience more annual influenza disease; and there was a seven-fold increase in Tamiflu prescriptions for children under 18 from 2004 to 2005.
Another finding of the investigation revealed a correlation between a physician's years out of medical school and his or her rate of Tamiflu prescribing. Older, more experienced physicians, regardless of specialty, prescribed more Tamiflu than younger, more recently trained physicians.
Tamiflu is an oral antiviral treatment, not a vaccine for influenza. The medicine can reduce the severity and duration of the illness if started within two days of the onset of flu symptoms. To prevent the flu, Tamiflu must be started within two days of the contact with someone who has the flu. When administered according to its approved dosage, Tamiflu delivers a 38 percent reduction in the severity of symptoms, a 67 percent reduction in secondary complications and a 37 percent reduction in the duration of the influenza illness. Tamiflu has been used by about 42 million people worldwide since its launch and mortality in patients taking Tamiflu both in adults and children is lower than in influenza patients who are not treated with Tamiflu. While laboratory studies have shown Tamiflu somewhat effective in treating avian flu, drug studies in humans are still needed to determine treatment efficacy and the best therapy regimen.
Source: Medco Health Solutions, Inc.