What is Tamiflu?
Tamiflu is a medicine containing the active substance oseltamivir. It is available as capsules (yellow: 30 mg; gray: 45 mg; yellow and gray: 75 mg) and as a powder for oral suspension (12 mg / ml).
What is Tamiflu used for?
Tamiflu is used in the treatment or prevention of influenza in patients over one year of age:
- in the treatment of influenza, it can be used in patients who show symptoms of influenza, when it is known that the influenza virus is circulating in the community, in the prevention of influenza, it can be used in patients who have been in contact with people affected. This is usually done on a case-by-case basis, but in exceptional circumstances, for example if the flu vaccine is not sufficient and in the presence of a pandemic (global epidemic of influenza), seasonal prevention may be considered.
During an influenza pandemic, Tamiflu can also be used to treat or prevent influenza in children under the age of one year. It is up to the doctors to decide whether to administer Tamiflu to children in this age group, depending on the severity of the illness triggered by the flu virus as well as the child's state of health, in order to ensure that the latter is likely to benefit from the medicine
Tamiflu is not a substitute for influenza vaccination, and its use must be based on official recommendations.
The medicine can only be obtained with a prescription.
How is Tamiflu used?
In the treatment of influenza, Tamiflu should be administered within the first two days after the onset of symptoms. The medicine should be taken in a single dose twice a day for five days.
In the prevention of influenza, Tamiflu should be administered within the first two days of contact with affected persons. The medicine should be taken in a single dose once a day for at least 10 days after contact with an infected individual. If Tamiflu is used during a flu epidemic, the dose can be given for up to six weeks.
The dose of Tamiflu for adults and children weighing more than 40 kg is 75 mg. For children weighing less than 40 kg, the dose is adjusted to their weight using lower dose capsules
(30 or 45 mg) or oral suspension. If the powder for oral suspension is not available, the pharmacist can prepare a solution using the contents of the capsules, or the contents of the capsules can be mixed at home with sweetened food. In patients with kidney problems it is necessary to reduce the doses. For all information, see the package leaflet.
How does Tamiflu work?
The active substance in Tamiflu, oseltamivir, acts specifically on the influenza virus, blocking some of the enzymes on its surface known as neuraminidases. When these enzymes are blocked, the virus cannot expand. Oseltamivir acts on the neuraminidase enzymes of influenza A (the most common) and B.
What studies have been carried out on Tamiflu?
Tamiflu has been compared with placebo (a dummy treatment) in studies on the treatment of influenza (conducted on 2, 413 adults and adolescents, 741 elderly and 1, 033 children at least one year old). Efficacy was measured using an evaluation sheet in which the symptoms (fever, muscle pain, headache, sore throat, cough, general malaise and runny nose) had to be noted.
In the prevention of influenza, Tamiflu was studied in patients who had been exposed to the disease because one of their relatives had contracted the virus (962 cases) or during an epidemic (1, 562 subjects aged between 16 and 65 and 548 elderly in retirement homes). The studies recorded the number of influenza cases demonstrated by laboratory tests. A study also investigated the use of Tamiflu in a family environment (277 families) both for the treatment of the affected person and for the treatment or prevention of influenza in people in contact with the patient.
A limited study was conducted to show that the recommended dose of Tamiflu in the blood of children aged one month and one year produces levels of medicine similar to effective doses in older children and adults. Tamiflu has not been studied in children younger than one month; however its use in this age group is based on the results observed in older children.
What benefit has Tamiflu shown during the studies?
In adult treatment studies, Tamiflu shortened the course of the disease by an average of 5.2 days in placebo-treated patients to 4.2 days in patients treated with Tamiflu. The average reduction in disease duration in children between one and six years was 1.5 days.
In prevention studies, Tamiflu reduced the incidence of influenza among people in contact with sick people. In the study conducted during an epidemic, only 1% of the people who took Tamiflu developed the flu after contact, compared with 5% of the subjects treated with placebo. In families with a member affected by the flu, 7% of cohabiting family members who had taken Tamiflu for preventive purposes developed the disease, compared to 20% of those who had not undergone any preventive treatment.
What is the risk associated with Tamiflu?
The most common side effects of Tamiflu in patients at least 13 years of age (seen in more than 1 patient in 10) are headache and nausea. In children aged one year to 12 years, the most common side effects (seen in more than 1 patient in 10) are vomiting and diarrhea; similar side effects are seen in children under one year of age. For the full list of all side effects reported with Tamiflu, see the Package Leaflet.
Tamiflu should not be used in people who are potentially hypersensitive (allergic) to oseltamivir or any of the other components.
Why has Tamiflu been approved?
The Committee for Medicinal Products for Human Use (CHMP) decided that the benefits of Tamiflu outweigh its risks in the treatment and prevention of influenza. The Committee therefore recommended that Tamiflu be given marketing authorization.
More information on Tamiflu:
On 20 June 2002, the European Commission granted a marketing authorization for Tamiflu, valid throughout the European Union, to Roche Registration Limited . After five years the marketing authorization was renewed for another five years.
The full EPAR for Tamiflu can be found here .
Last update of this summary: 10-2009.
