Review raises questions about why government stockpiling zanamivir, oseltamivir

Zanamivir and oseltamivir (Tamiflu, Roche) can help prevent and treat the symptoms of influenza, but there is not enough information to evaluate the drugs’ safety and efficacy for preventing the spread of flu or pneumonia, according to a new review published online January 18.

The review, published by The Cochrane Summaries and conducted by The Cochrane Collaboration, questions the U.S. government’s stockpiling of Tamiflu to treat flu outbreaks in the future.

Roche has not provided a full set of clinical study reports to the Cochrane Review in order for researchers to fully analyze the safety and efficacy of clinical trials, according to the Cochrane Collaboration. However, based on the documents the organization did review, “there were substantial problems with the design, conduct, and availability of information” from many of the trials, according to The Cochrane Summaries abstract.

Because researchers were not able to conduct a full meta-analysis of all data on oseltamivir, they analyzed the drug’s effect on symptoms and hospitalizations. Oseltamivir shortens symptoms by about 21 hours and there are no effects on hospitalizations, according to the researchers.

“Our independent analysis concurs with the conservative conclusions regarding the effects of both drugs by FDA. FDA only allowed claims of effectiveness of both drugs for the prevention and treatment of symptoms of influenza and not on other affects (such as interruption of person-to-person spread of the influenza virus or prevention of pneumonia),” according to the abstract.

In addition, there is evidence to suggest that both drugs are associated with harmful effects, including nausea, vomiting, and asthma, the researchers wrote.