According to FDA: "Tamiflu (oseltamivir phosphate) is an oral anti-viral drug approved for the treatment of acute, uncomplicated influenza in patients 2 weeks of age and older whose flu symptoms have not lasted more than two days. This product is approved to treat Type A and B influenza."

Oseltamivir is in a class of medications called neuraminidase inhibitors. It halts the spread of the flu virus in the body. Rather than for treating Type A and Type B influenza, Oseltamivir also may be used to treat and prevent infections from influenza A (H1N1). So during the H1N1 swine flu epidemic in 2009, Tamiflu sales increased considerably.

Due to find drug's efficacy for the treatment of seasonal influenza in adults, a meta-analysis of randomized controlled trials was conducted by a US-British research team with Prof. Arnold S. Monto as senior author. The research team members were as follows: -Joanna Dobson, Department of Medical Statistics, London School of Hygiene & Tropical Medicine, UK; -Prof. Richard J. Whitley, Department of Pediatrics, Microbiology, Medicine and Neurology, University of Alabama, US; -Prof Stuart Pocock, Department of Medical Statistics, London School of Hygiene& Tropical Medicine, UK; -Prof. Arnold S. Monto, Department of Epidemiology, University of Michigan, School of Public Health, USA

Funded by Multiparty Group for Advice on Science (MUGAS), the researchers used and analyzed data made available by Roche (drug's manufacturer).

The research team analyzed nine trials including 4328 patients. They found following taking normal prescribed dosage of Oseltamivir, the duration of the illness reduces by 21% (The median times to alleviation were 97.5h for Oseltamivir and 122.7h for Placebo group.) Treated patients with Oseltamivir, experiences lower respiratory complications requiring antibiotics. (4.9% Oseltamivir vs. 8.7% Placebo). Furthermore, patient's hospitalization is reduced by 63% following taking Tamiflu.

Regarding safety, Oseltamivir increased the risk of nausea by 9.9% and vomiting by 8.0% comparing to 6.2% and 3.3% in Placebo group respectively. The research team did not find raised neurological disorders among Oseltamivir group.

The study was published in The Lancet on 29 January 2015.

Although Oseltamivir significantly reduces flu impact, precautions should be taken because of increased risk of nausea and vomiting following taking the medication.

In an accompanying editorial, Heath Kelly from the Australian National University in Canberra and Benjamin Cowling from The University of Hong Kong say, "The rational use of oseltamivir is becoming clear…Because benefits accrue only to patients with laboratory-confirmed influenza, but the risk of adverse events is increased in all patients, rapid diagnostic testing, if available, is advisable before oseltamivir administration in routine clinical practice…In a pandemic or severe epidemic, oseltamivir can be used presumptively when there is a high probability that influenza-like illness is caused by influenza virus infection and when the outcome of infection is likely to be severe, but a proven strategy for rapid distribution needs to accompany any plan that proposes widespread use of oseltamivir."

News source: The Lancet, Science Daily, AAAS, EurekAlert

Dr. Shima Naghavi, Director of International Affairs