Amantadine, oseltamivir and zanamivir for the treatment of influenza

Oseltamivir and zanamivir are recommended, within their marketing authorisations, for the treatment of influenza in adults and children if all the following circumstances apply:

• national surveillance schemes indicate that influenza virus A or B is circulating (the Health Protection Agency in England [and the equivalent bodies in Wales and Northern Ireland] uses information from a range of clinical, virological and epidemiological influenza surveillance schemes to identify periods when there is a substantial likelihood that people presenting with an influenza-like illness are infected with influenza virus)

• the person is in an 'at-risk' group as defined in 1.2

• the person presents with an influenza-like illness and can start treatment within 48 hours (or within 36 hours for zanamivir treatment in children) of the onset of symptoms as per licensed indications.

For the purpose of this guidance, people 'at risk' are defined as those who have one of more of the following:

• chronic respiratory disease (including asthma and chronic obstructive pulmonary disease)

• chronic heart disease

• chronic renal disease

• chronic liver disease

• chronic neurological conditions

• diabetes mellitus.
  
  People who are aged 65 years or older and people who might be immunosuppressed are also defined as 'at-risk' for the purpose of this guidance.

The choice of either oseltamivir or zanamivir in the circumstances described in 1.1 should be made after consultation between the healthcare professional, the patient and carers. The decision should take into account the patient's preferences regarding drug delivery and potential adverse effects and contraindications. If all other considerations are equal, the drug with the lowest acquisition cost should be offered.

During localised outbreaks of influenza-like illness (outside the periods when national surveillance indicates that influenza virus is circulating in the community), oseltamivir and zanamivir may be offered for the treatment of influenza in 'at-risk' people who live in long-term residential or nursing homes. However, these treatments should be offered only if there is a high level of certainty that the causative agent in a localised outbreak is influenza (usually based on virological evidence of influenza infection in the initial case).

Amantadine is not recommended for the treatment of influenza.