Giving double doses of the antiviral drug oseltamivir (Tamiflu) offers no clinical or virological advantages over a standard dose for patients admitted to the hospital with severe influenza infection, according to a study.
The study, published May 30 on the website of the British Medical Journal, was described as the first to look at the effectiveness of higher doses of oseltamivir in cases of severe flu infection. The researchers said the findings have implications for global guidelines on clinical management and stockpiling drugs for pandemic preparedness, including the current outbreak of the H7N9 virus in China.
Prior research has shown that early treatment with oseltamivir is beneficial for patients with uncomplicated flu infection and improves survival in hospitalized patients with severe infection. This finding has led some authorities to recommend double doses of oseltamivir for treatment of patients with severe flu infections.
The study, conducted by researchers from the South East Asia Infectious Diseases Clinical Research Network, involved 326 patients with severe flu infection at 13 hospitals in Indonesia, Singapore, Thailand and Vietnam. Most of the patients were children younger than 15.
Patients were given either a standard dose or double dose of oseltamivir for five days. Their virus levels were monitored for the duration of the treatment along with other outcomes, such as admission to intensive care, the need for mechanical ventilation to assist with breathing and death.
The findings revealed no difference in virus levels at day five between either of the treatment groups. There also were no clinical differences in outcomes, including need for ventilation, time in hospital, rate of death or rates of adverse events between the different doses.
“The recommendation to give higher doses of oseltamivir to severe cases of flu infection has major implications for clinical management, public health and planning for antiviral stockpiles, but has not been grounded in evidence,” Jeremy Farrar, a professor and the director of the South East Asia Infectious Disease Clinical Research Network, said in a news release. “Our findings do not support routine use of double doses to treat severe flu infections, which could help to conserve drug stocks in the event of a pandemic.”
The study was funded by the Wellcome Trust, U.S. National Institute of Allergy and Infectious Diseases and the Singapore National Medical Research Council.
Read the study: www.bmj.com/content/346/bmj.f3039.