Alerts and Actions

October 2005

H5N1 infections, Relenza® and Tamiflu® - Hedging our risks or risking our only hedge?

Medication Safety Actions:
Tamiflu® and Relenza® prescriptions, orders and supplies should be closely monitored as an indicator of public concern and the need for practitioner education. Physician offices and consumers should be counseled to not stockpile or use these drugs as prophylaxis against any form of flu (seasonal influenza or avian influenza). Pharmacists should only fill prescriptions for the bona fide medical treatment of influenza A while considering the risks associated with antiviral use in each patient.

Background
A recent Google search retrieved over 17,000 articles that are increasing public awareness of the risks and the potential for deadly pandemics of the avian flu. Numerous reports are raising public fears to the point that Tamiflu® (oseltamivir) and Relenza® (zanamivir) are being stockpiled by physicians and individual consumers in addition to governments worldwide.

Influenza A (H5N1) is a subtype of type A influenza virus, commonly known as the avian (bird) flu. This highly pathogenic virus was first isolated from infected birds in South Africa in 1961 and the first known case of transmission to humans was reported in 1997. More recent strains are showing increased capability of infecting mammals and longer latency between viral shedding and the onset of symptoms. These trends suggests that persons can unknowingly become infected and transmit the virus to others. The majority of known human infections have presented with respiratory symptoms and one unusual fatal case has presented as encephalitis in a child in Viet Nam in 2004. There are no vaccines to protect humans against the avian flu; however an experimental vaccine is under development in the United States. The CDC and the World Health Organization regularly provide updates on avian flu.

Talking Points
The avian flu has not spread to humans in any manner or magnitude that can be described as an outbreak or epidemic. Current strains of H5N1 influenza are believed generally susceptible to Tamiflu® (oseltamivir) and Relenza® (zanamivir); however resistance has already emerged to oseltamivir in some human cases. Future H5N1 strains of influenza may emerge in a form that are resistant to currently available antivirals. Overall, spending money to stockpile these expensive medications to hedge against a possible future outbreak is a questionable way to use limited healthcare dollars. Hedging the risks of infection by inappropriately using these drugs now, may risk the only effective hedge available to treat future infections.