Recommendations for Use of Antiviral Medicines
With regard to the recent influenza A/H1N1 pandemic, the Committee for Medicinal Products of the Agency for Medicinal Products and Medical Devices adopted on its 111 Meeting the recommendations for use of the antiviral medicinal product Tamiflu (oseltamivir) in children under the age of one and medicinal products Tamiflu and Relenza (zanamivir) in pregnant and breastfeeding women in case of an influenza A/H1N1 pandemic (pandemic alert level six according to the World Health Organisation classification). Recommendations are in accordance with the recommendations of the Committee for Human Medicinal Products (CHMP) of the European Medicines Agency (EMA).
Tamiflu is authorised to treat or prevent influenza A/H1N1 in adults and children over the age of one year. Relenza is another medicine authorised to treat and prevent influenza in adults and children from the age of five years. Active substances in these medicinal products (oseltamivir and zanamivir), act as neuraminidase inhibitors , the enzyme of the virus surface. Associating with the enzyme, they block its further spread. Both medicines have shown to be efficient in treating the new influenza virus.
Taking account of the potential that the influenza A/H1N1 virus possesses in causing pandemic, the CHMP has reviewed the justified use of Tamiflu and Relenza in children under the age of one, pregnant and breastfeeding women.
Children under the age of one
There is less evidence to support the use of Tamiflu in the treatment of children of this group of age and taking into account that Relenza is authorised in children over f years, only Tamiflu is taken into consideration that is authorised in children from the age of 5, only Tamiflu that is authorised in children from the age of 1, was taken into consideration. In order to assess the efficacy and safety of use of Tamiflu, the results of one on-going clinical trial on children under the age of one and two completed clinical trials and one retrospective analysis were taken into account.
Recommendations are as follows:
- There is enough evidence that substantiate the justification of use of Tamiflu in the treatment of children under the age of one in influenza A/H1N1 pandemic.
- There is less evidence with regard to use of Tamiflu in post-exposition profilaxis of influenza in children under the age of one. Therefore, it is recommended that in children under the age of one, the profilaxis with Tamiflu does not last longer than 10 days.
- In case where there is a need to prescribe Tamiflu to children under the age of one, it is recommended to assess the benefit/risk ratio for every infant individually.
- Should Tamiflu be prescribed to this group of children, the recommended dosage is 2 to 3 mg per kg body weight once a day for 10 days.
- Should a child under the age of one be treated with Tamiflu in a pandemic, it should be hospitalised and under medical supervision. However, it is recommended from practical reasons that every infant under the age of 3 months be hospitalised.
Pregnant and breastfeeding women
The evidence about the use of Tamiflu and Relenza in the treatment and profilaxis of pregnant and breastfeeding women is also limited. In order to assess the safety and efficacy in a pandemic, post-marketing data about the safe use in patients taking Tamiflu (232 patients), or Relenza (97 patients) during pregnancy or breastfeeding have been analysed.
Recommendations are as follows:
- There is enough evidence that substantiate the justification of use of Tamiflu and Relenza in pregnant and breastfeeding women, which means that demonstrate that the benefits of using these benefits outweigh the risks in case of an influenza A/H1/N1.
- In case where Tamiflu is used for the treatment of pregnant and breastfeeding women, the correct dosage is 75 mg twice a day during five days.
- In case where Tamiflu is used for the treatment of pregnant and breastfeeding women, the correct dosage is two inhalations per day (2x5 mg) during five days.
Important: The above mentioned recommendations for use in children under the age of one and pregnant and breastfeeding women are valid exclusively for an influenza A/H1N1 pandemic, according to the classification of the WHO. Tamiflu and Relenza in a non-pandemic situation should be used exclusively according to the current Summary of Product Characteristics. These recommendations, neither at the European Medicines Agency's level, nor at the Croatian Agency for Medicinal Products and Medical Device's level do not imply any changes in the marketing authorisation for these medicines or their indications.
The extension of shelf life of Tamiflu 75 mg, 45 mg and 30 mg hard capsules
According to the recommendations of the European medicines Agency (EMA), the shelf life of Tamiflu hard capsules is being extended from the current 5 to 7 years. The Agency for Medicinal Products and Medical Devices (HALMED) has approved this change for all pharmaceutical forms of hard capsules currently authorised in Croatia (Tamiflu 75 mg, 45 mg and 30 mg). The change will be included in the Summary of Product Characteristics, Labelling and package Leaflet of all newly manufactured product batches.
For Tamiflu packages already on the market, according to the EMA's CHMP (Committee for Medicinal Products for Human Use), the Agency for Medicinal Products and Medical Devices recommends a maximal two more storage years, after the expiration of the labelled five years shelf life.
Patients having a Tamiflu package at home may use it for two more years after the expiry of the shelf life labelled on the packaging.
The extension of shelf life of Relenza (zanamivir)
The Agency for Medicinal Products and Medical Devices (HALMED) has authorised the extension of shelf life of Relenza (zanamivir) inhalation powder, from the current 5 to 7 years.
For Relenza packages on the market, according to the recommendations of the Co-ordination Group for Mutual Recognition and Decentralised Procedure - human (CMDh), the Agency for Medicinal Products and Medical Devices recommends the storage for a maximal two more years after the expiry of the five years shelf life labelled on the packaging.