Influenza treatment

Patients with suspected influenza should be isolated and respiratory precautions commenced – see here for advice.
If potential Avian Influenza (e.g. History of travel to SE Asia or S Asia), Discuss urgently with Micro/ID; see Triage of HCID.
The RECOVERY trial includes patients with influenza. To contact the RECOVERY research team use emergency.research@oxnet.nhs.uk or ext 22003. When prescribing for patients in the trial use the RECOVERY trial PowerPlan on EPR.

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Patient group

Recommendation

Uncomplicated (most healthy adults)

Do not treat

Complicated:

Influenza requiring admission to hospital
Signs/symptoms of pneumonia (hypoxaemia, dyspnoea, lung infiltrate)
Central nervous system involvement
Significant exacerbation of an underlying medical condition (e.g. COPD)

If within 48 hours symptom onset: Treat

If 2-5 days after symptom onset: can discuss starting treatment Micro/ID

More than 5 days after symptom onset: Do not treat

At risk of complicated influenza:

Neurological, hepatic, renal, pulmonary and chronic cardiac disease
Diabetes mellitus
Severe immunosuppression
Age over 65 years
Pregnancy (including up to 2 weeks post-partum)
Morbid obesity (BMI 40 or more)

If within 48 hours symptom onset: Treat

If 2-5 days after symptom onset: can discuss starting treatment with Micro/ID

More than 5 days after symptom onset: Do not treat

All use of antivirals must be as per UKHSA guidance on use of antiviral agents for the treatment and prophylaxis of seasonal influenza. Any use outside of this should be discussed with Micro/ID.

Preferred

Uncomplicated: No treatment (no evidence of benefit).

Complicated / At risk of complicated: oseltamivir 75mg po bd for 5 days (10 days for immunosuppressed patients)

For dosing in adult patients 40kg or less: 60mg po bd for 5 days (10 days for immunosuppressed patients)
For dosing in renal impairment see oseltamivir drug monograph

Treatment of influenza in at risk and severely immunocompromised patients should be started promptly when influenza is suspected rather than waiting for positive test results.

Alternative (complicated influenza in severely immunosuppressed patients)

Zanamivir either inhaled (10mg bd inhaled) or IV (600mg bd iv).

For IV dosing in renal impairment see Zanamivir drug mongraph

Consider Zanamivir if:

poor clinical response to oseltamivir
evidence of gastrointestinal dysfunction
subtype testing confirms a strain with potential oseltamivir resistance (e.g. A [H1N1] pdm09).

Eligibility for treatment

Drug Treatment

Preferred

Alternative (complicated influenza in severely immunosuppressed patients)

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