Oseltamivir

File:A Tamiflu (oseltamivir) capsule.jpg

A oseltamivir capsule

A package of capsules

Oseltamivir, sold under the brand name Tamiflu, is an antiviral medication used to treat and prevent influenza A and influenza B (flu). Many medical organizations recommend it in people who have complications or are at high risk of complications within 48 hours of first symptoms of infection. They recommend it to prevent infection in those at high risk, but not the general population. The CDC recommends that clinicians use their discretion to treat those at lower risk who present within 48 hours of first symptoms of infection. It is taken by mouth, either as a pill or liquid.

Controversy and Recommendations

Recommendations regarding oseltamivir are controversial, as are criticisms of the recommendations. A 2014 Cochrane review concluded that oseltamivir does not reduce hospitalizations, and that there is no evidence of reduction in complications of influenza. Two meta-analyses have concluded that benefits in those who are otherwise healthy do not outweigh its risks. They also found little evidence regarding whether treatment changes the risk of hospitalization or death in high-risk populations. However, another meta-analysis found that oseltamivir was effective for prevention of influenza at the individual and household levels.

Side Effects

Common side effects include vomiting, diarrhea, headache, and trouble sleeping. Other side effects may include psychiatric symptoms and seizures. In the United States, it is recommended for influenza infection during pregnancy. It has been taken by a small number of pregnant women without signs of problems. Dose adjustment may be needed in those with kidney problems.

Approval and Usage

Oseltamivir was approved for medical use in the US in 1999. It was the first neuraminidase inhibitor available by mouth. It is on the complementary list of World Health Organization's List of Essential Medicines, indicating a lower cost-benefit ratio. A generic version was approved in the US in 2016. As of 2014, the wholesale cost in the developing world was about US$4.27 per day. The wholesale cost for a course of treatment in the United States is about US$54.00 as of 2019. In 2016, it was the 249th most prescribed medication in the United States with more than a million prescriptions.

Mechanism of Action

Oseltamivir is a neuraminidase inhibitor, a competitive inhibitor of influenza's neuraminidase enzyme. The enzyme cleaves the sialic acid which is found on glycoproteins on the surface of human cells that helps new virions to exit the cell. Thus, oseltamivir prevents new viral particles from being released.

See Also

• Antiviral medication
• Influenza A
• Influenza B
• Neuraminidase inhibitor
• CDC