The infection that causes influenza is treated by a medication known as Tamiflu which belongs to a group of medicines called neuraminidase inhibitors attacking the influenza virus and preventing it from spreading inside the body. Tamiflu attacks the virus that causes the flu at its source, rather than simply masking symptoms. Tamiflu capsules are coloured grey/light yellow and each one contains 75 mg of the active drug which is taken by mouth. For people who have difficulty swallowing tablets, Tamiflu is available in liquid suspension form.

Being an antiviral drug Tamiflu is used in the treatment and prophylaxis of both Influenza virus A and Influenza virus, Tamiflu, like zanamivr is a neuraminidase inhibitor and acts as a transition-state analogue inhibitor of influenza neuraminidase, which prevents new viruses from emerging from infected cells. Currently Tamiflu is the only medication that has been proven to fight the Bird Flu.

Tamiflu was developed by Gilead Sciences and is marketed by Hoffmann-La Roche it was the first orally active neuraminidase inhibitor commercially developed. Tamiflu is a considered a prodrug which is hydrolysed hepatically to the active metabolite, the free carboxylate of oseltamivir (GS4071).

A new influenza pandemic is considered to be a distinct possibility to spread around the world and because of this, Tamiflu has received substantial media attention. Because production capacity is limited and as the drug has been proved to be successful, governments are stockpiling. The drug cannot be given out freely and it has to be prescribed by a doctor.

Tamiflu should not be given to children under one year old and there are reports are that it may have an adverse effect on infants under that age. Tamiflu is indicated for the treatment of influenza A and B virus in people of at least one year of age, and the prevention of influenza in people at least 1 year or older.

Tamiflu may cause mild-to-moderate nausea or vomiting in one out of ten people but is generally well tolerated. By taking the medication with food helps reduce the potential for these side effects and not on an empty stomach. Occasionally reported effects may include bronchitis, sleeplessness and vertigo.

Some common adverse drug reactions associated with Tamiflu includes nausea, vomiting, diarrhea, abdominal pain, and headache. There are rare adverse drug reactions which include hepatitis and elevated liver enzymes, rash, allergic reactions including anaphylaxis, and Stevens-Johnson syndrome.

Very rare, but reported are toxic epidermal necrolysis, cardiac arrhythmia, seizure, confusion, aggravation of diabetes, and haemorrhagic colitis and there have been some neurological effects reported as well.