Health Advisory
2009-2010 Influenza Season Update #9
Recommendations for Use of Antiviral Medications - Extended Use Authorization for Peramivir

To: Vermont Health Care Provider
From: Wendy Davis, MD, Commissioner
Date: November 6, 2009

– Please Distribute Widely –

On October 16, 2009, the Centers for Disease Control & Prevention (CDC) updated their guidance for early empiric antiviral treatment in people with suspected influenza who are at increased risk of developing severe complications.

The 2009 H1N1 influenza virus continues to be the dominant virus in circulation in the U.S, and in Vermont: http://www.healthvermont.gov/prevent/flu/flusurveillance.aspx#lab

Recommendations for Use of Antiviral Medications
CDC’s recommendations were updated to provide additional guidance for clinicians in prescribing antiviral medications for treatment and prevention of influenza during the 2009-2010 season. In general, the priority use of antiviral medications during this season continues to be in people who are hospitalized with influenza and those at increased risk of influenza-related complications, as outlined in the recommendations last updated on Septempter 22, 2009. This document has been updated to:

  1. Clarify treatment and chemoprophylaxis considerations for persons vaccinated with the 2009 H1N1 and seasonal influenza vaccines.
  2. Include women up to 2 weeks postpartum at higher risk for complications from 2009 H1N1 influenza.
  3. Provide additional oseltamivir dosing instructions for children younger than 1 year of age.
  4. Review adverse events and contraindications associated with oseltamivir and zanamivir.

This document should be considered interim, and will be updated as needed.

When treatment of influenza is indicated in a patient with suspected influenza, health care providers should initiate empiric antiviral treatment as soon as possible. Waiting for laboratory confirmation of influenza to begin treatment with antiviral drugs is not necessary. Patients with a negative rapid influenza diagnostic test should be considered for treatment if clinically indicated because a negative rapid influenza test result does not rule out influenza virus infection. The sensitivity of rapid influenza diagnostic tests for 2009 H1N1 virus can range from 10% to 70%, indicating that false negative results occur frequently.

Treatment, when indicated, should be started as early as possible because the benefits are greatest when started within the first 2 days of illness. However, some studies of hospitalized patients with seasonal and 2009 H1N1 influenza have suggested benefit of antiviral treatment even when treatment was started more than 48 hours after illness onset.

All hospitalized patients with suspected or confirmed 2009 H1N1 should receive antiviral treatment with a neuraminidase inhibitor – either oseltamivir or zanamivir – as early as possible after illness onset.

Who should have priority for treatment with influenza antiviral drugs?
Early empiric treatment with oseltamivir or zanamivir is recommended for anyone with suspected or confirmed influenza that requires hospitalization. Prompt empiric outpatient antiviral therapy is also recommended for people with suspected influenza who have symptoms of lower respiratory tract illness or clinical deterioration, regardless of previous health or age. Early empiric treatment should be considered for anyone at higher risk for complications – even if not hospitalized – including:

Clinical judgment should guide antiviral treatment decisions for ill people who are not at higher risk for complications from influenza.
CDC’s guidance for clinicians: http://www.cdc.gov/H1N1flu/recommendations.htm

Extended Use Authorization for Peramivir
The Food & Drug Administration (FDA) has issued an Extended Use Authorization (EUA) for the unapproved drug peramivir to be used in certain hospitalized adult and pediatric patients to treat 2009 H1N1 influenza. Peramivir is still in Phase 3 clinical trials, but data on efficacy and safety were deemed sufficient by FDA for the EUA. Authorized Emergency Use of peramivir may be sought by contacting CDC directly and must be consistent with each of the terms of the EUA. For more information see: www.cdc.gov/h1n1flu/eua/peramivir.htm

Key points from FDA’s Extended Use Authorization:

The EUA documentation contains other important use and documentation requirements, including dosing for pediatric patients.

To seek access to peramivir or for more information: www.cdc.gov/h1n1flu/eua/peramivir.htm

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