Oseltamivir

How it works

It is a prodrug converted to oseltamivir carboxylate, which inhibits the influenza neuraminidase enzyme, preventing release of new viral particles from infected cells and limiting spread.

Prescribing in practice

• The most important paediatric point is that treatment is most effective when started promptly after symptom onset, and it is generally reserved for at-risk children or during recognised influenza circulation as advised by national guidance.
• Dose is weight- and age-based and requires adjustment in renal impairment; doses should be confirmed against a children's formulary, and a suspension is available for young children.
• Nausea and vomiting are common, and neuropsychiatric events such as confusion or abnormal behaviour have been reported, so children should be observed for unusual behaviour.

Monitoring

Monitor for clinical response, gastrointestinal tolerance and any neuropsychiatric or behavioural changes during treatment.

Counselling the patient

• Start as soon as possible after symptoms begin for the best effect.
• Giving with food can reduce nausea, and a liquid is available for younger children.
• Report any confusion, agitation or abnormal behaviour.

Evidence & guidelines

Use of oseltamivir for at-risk children during influenza circulation is supported by NICE technology appraisal guidance and UK public-health recommendations.