No Added Benefit To Doubling Up On Tamiflu Antiviral Drugs
May 31, 2013

No Added Benefit To Doubling Up On Tamiflu Antiviral Drugs

Brett Smith for - Your Universe Online

Patients with a severe or deadly case of the flu are often prescribed the antiviral drug Tamiflu; but there are no additional benefits to taking a double dose of the drug, according to a new study from researchers at the South East Asia Infectious Diseases Clinical Research Network (SEAICRN).

The study´s findings, which were published in the British Medical Journal (BMJ), conflict with the recommendations of some experts who have called for higher doses of the drug in serious flu cases.

The study represents the first randomized clinical trial to study the issue of higher dosage and it has implications for the global preparation to mitigate a potential flu pandemic, according to researchers.

"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," said Jeremy Farrar, director of the network of researchers. “The recommendation to give higher doses of (Tamiflu) 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.”

The study comes just as flu experts are keeping their eye on a new H7N9 strain of bird flu that has killed 36 people in China so far. The H7N9 virus has not been seen spreading easily from person to person and cases of the disease appear to be receding. However, experts have expressed concern that the virus may be able to quickly develop a resistance to Tamiflu.

Research has shown that early-onset treatments with Tamiflu help to speed recovery in both seasonal and pandemic flu. It has also been shown to improve survival rates for patients hospitalized by the virus.

The study, which took place between April 2007 and February 2010, examined over 320 patients with severe flu symptoms in Indonesia, Singapore, Thailand and Vietnam who were administered either a standard dose or double dose of Tamiflu for five days. The patients´ virus levels were monitored for the duration of the treatment and researchers also looked at patient admissions to intensive care, the need for respiration assistance and patient death. The researchers were not able to detect a difference in either the virus levels or clinical outcomes between the two dosage groups.

In their conclusion, the researchers said that Tamiflu could be reaching a saturation point in the body and a single dose could be producing a maximum antiviral effect. The authors also cited the limited scope of their study cohort and a possible limiting factor.

“The heterogeneous population characteristics, geographical differences in recruitment (most patients were from Vietnam but there were no significant differences between Vietnam and other sites), and the variety of infecting viruses in our trial reflect the clinical circumstances in South East Asia during our study but might be viewed as a limitation,” the researchers wrote.

While most people that are infected with flu will recover between a few days and two weeks, some patients develop complications that result in hospital admission.