Tamiflu

Oseltamivir (INN) (pronounced is an antiviral drug that slows the spread of influenza (flu) virus between cells in the body by stopping the virus from chemically cutting ties with its host cell. The drug is sold under the trade name Tamiflu and is taken orally in capsules or as a suspension. It has been used to treat and prevent Influenzavirus A and Influenzavirus B infection in over 50 million people since 1999.[citation needed] Oseltamivir becomes active in the body once it passes through the liver.
Oseltamivir was the first orally active neuraminidase inhibitor commercially developed. It was developed by C.U. Kim, W. Lew and X. Chen of US based Gilead Sciences and is currently marketed by Hoffmann–La Roche (Roche). In Japan, it is marketed by Chugai Pharmaceutical Co., which is more than 50% owned by Roche.
As of October 2009, only 39 out of over 10,000 samples of the prevalent 2009 pandemic H1N1 (swine) flu tested worldwide have shown resistance to oseltamivir, contrasting sharply with the 99.6% of the 2008 seasonal H1N1 flu strains tested which have resistance to oseltamivir.
Oseltamivir is marketed by Roche under the trade name Tamiflu, as capsules (containing oseltamivir phosphate 98.5 mg equivalent to oseltamivir 75 mg) and as a powder for oral suspension (oseltamivir phosphate equivalent to oseltamivir 12 mg/ml).
Tamiflu is indicated for the treatment and prevention of infections due to influenza A and B virus.
Tamiflu is approved for use in persons age 1 and over. There is also currently an FDA Emergency Use authorization temporarily allowing the use of Tamiflu in children less then one year old. The usual adult dosage for treatment of influenza is 75 mg twice daily for 5 days, beginning within 2 days of the appearance of symptoms and with decreased doses for children and patients with renal impairment. Oseltamivir may be given as a preventive measure either during a community outbreak or following close contact with an infected individual. Standard prophylactic dosage is 75 mg once daily for patients aged 13 and older, which has been shown to be safe and effective for up to six weeks. The importance of early treatment is that the NA protein inhibition is more effective within the first 48 hours. If the virus has replicated and infected many cells the effectiveness of this medication will be severely diminished, especially over time.
The Centers for Disease Control and Prevention (CDC) recommends physicians prioritize which patients they prescribe Tamiflu to. Specifically, people hospitalized with more severe illness, children younger than 2 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 that children and adults presenting with suspected flu that have symptoms of lower respiratory tract illness or clinical deterioration should also receive prompt empiric antiviral therapy, regardless of previous health or age.
Tamiflu is a prodrug, which is hydrolysed hepatically to the active metabolite, the free carboxylate of oseltamivir (GS4071).
Tamiflu is a neuraminidase inhibitor, serving as a competitive inhibitor towards sialic acid, found on the surface proteins of normal host cells. By blocking the activity of the neuraminidase, oseltamivir prevents new viral particles from being released by infected cells.
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. Accordingly, it has been suggested that higher doses and longer durations of therapy should be used for treatment of patients with the H5N1 virus. And the best medicine to reduce and be free from SWINEFLU is TAMIFLU because it has got the capacity to fight against swineflu disease.