Oseltamivir is a prodrug, a (relatively) inactive chemical which is converted into its active form by metabolic process after it is taken into the body. It was the first orally active neuraminidase inhibitor commercially developed.[citation needed] It was developed by C.U. Kim, W. Lew, and X. Chen of US-based Gilead Sciences,[2] and is marketed by Genentech.[3] In Japan, it is marketed by Chugai Pharmaceutical Co.[citation needed]
As of December 15, 2010, the World Health Organization (WHO) reported 314 samples of the prevalent 2009 pandemic H1N1 flu tested worldwide have shown resistance to oseltamivir.[4]
Oseltamivir is indicated for the treatment and prevention of infections due to influenza A and B viruses.[5] Its effectiveness however is difficult to determine as the manufacturer, Hoffmann–La Roche, has refused to release study data for independent analysis.[6]
The Centers for Disease Control and Prevention recommends physicians prioritize which patients to whom they prescribe oseltamivir: specifically, people hospitalized with more severe illness, children younger than two years old, adults over 65, pregnant women, people with certain chronic medical or immunosuppressive conditions and adults under 19 on long-term aspirin therapy. However, they also advise children and adults presenting with suspected flu who have symptoms of lower respiratory tract illness or clinical deterioration should also receive prompt empiric antiviral therapy, regardless of previous health or age.[7]
The standard recommended dose incompletely suppresses viral replication in at least some patients with H5N1 avian influenza, increasing the risk of viral resistance and rendering therapy less effective.[8] Accordingly, higher doses and longer durations of therapy have been suggested for treatment of patients with the H5N1 virus.[8][9]
Clinical trials for an increased dosage began in May 2007. All avian influenza cases in Indonesia, Thailand, and Vietnam were inducted into the trial. The trial also included 100 cases of severe seasonal influenza from each of those countries and the United States. Half received the current standard dose, and half received a double dose, but for the standard length of time.[10]
results are not yet available.
/ɒsəlˈtæmɨvɪər/), an antiviral drug, slows the spread of influenza (flu) virus between cells in the body by stopping the virus from chemically cutting ties with its host cell; median time to symptom alleviation is reduced by 0.5–1 day.[1] The drug is marketed under the trade name Tamiflu, and is taken orally in capsules or as a suspension. It has been used to treat and prevent influenza A virus and influenza B virus infection in over 50 million people since 1999.[citation needed]