2010-11 Influenza Season

As Flu Activity Rises, CDC Updates Recommendations for Antiviral Medication Use

February 16, 2011 03:30 pm News Staff
Check Out AAFP Flu Resources

American Family Physician's AFP By Topic feature offers up-to-date clinical content related to seasonal influenza (some content available to members and paid subscribers only). Topics covered include vaccination, diagnosis, treatment, telephone triage and coding.

The Academy also has resources to help educate patients about flu prevention. FamilyDoctor.org's influenza Web page(familydoctor.org) covers numerous topics, including which groups are at high risk for flu complications, vaccination information and the use of antiviral medications.

No one knows better than practicing family physicians that flu activity is spiking in many parts of the country, but what FPs may not know is that the CDC has updated its recommendations for the use of antiviral agents for the treatment and chemoprophylaxis of influenza(www.cdc.gov). The agency also has issued new recommendations regarding the use of these medications specifically in pregnant and postpartum women(www.cdc.gov).

The CDC reported(www.cdc.gov) Feb. 11 that 37 states had widespread influenza activity during the week ending Feb. 5, and nine states had regional influenza activity. Visits to physicians for influenza-like illness also increased, with nine of 10 regions reporting activity at or above baseline levels.

The proportion of deaths attributed to pneumonia and influenza was at the epidemic threshold for that week, according to the CDC, and 11 flu-associated pediatric deaths were reported.

The agency published the antiviral recommendations of its Advisory Committee on Immunization Practices in the Jan. 21 Morbidity and Mortality Weekly Report. Six principal changes or updates from the agency's previous recommendations are featured:

  • Antiviral treatment is recommended as soon as possible for patients with confirmed or suspected influenza who have severe, complicated or progressive illness or who require hospitalization.
  • Antiviral treatment is recommended as soon as possible for outpatients with confirmed or suspected influenza who are at higher risk for influenza complications(www.cdc.gov).
  • The neuraminidase inhibitors oseltamivir and zanamivir are recommended because viral surveillance and resistance data indicate more than 99 percent of circulating influenza virus strains are sensitive to these medications. Amantadine and rimantadine should not be used because of high levels of resistance to these drugs among circulating influenza A viruses.
  • Antiviral resistance patterns can change over time, so clinicians should monitor local antiviral resistance surveillance data.
  • Oseltamivir may be used for treatment or chemoprophylaxis of influenza among infants less than 1 year old when indicated.
  • Antiviral treatment also may be considered on the basis of clinical judgment for any outpatient with confirmed or suspected influenza who does not have known risk factors for severe illness if treatment can be initiated within 48 hours of illness onset.

In its updated recommendations for antiviral drug use by obstetric health care professionals, the CDC said available data suggest that although oseltamivir and zanamivir are pregnancy category C medications, these medications are not teratogenic.

Furthermore, data from the 2009-10 flu season indicate that pregnant women with confirmed or suspected flu who were treated early with antiviral medications were less likely to be admitted to an intensive care unit and less likely to die. Therefore, said CDC officials, pregnant women with suspected or confirmed influenza should receive antiviral therapy as early in the course of disease as possible.

The agency also made the following recommendations regarding pregnant and postpartum women:

  • Women should be considered to be at increased risk of influenza-related complications for as long as two weeks postpartum, including after pregnancy loss.
  • Treatment with antiviral medications is recommended for pregnant or postpartum (i.e., as long as two weeks) women who have suspected or confirmed influenza. The medications can be taken during any trimester.
  • Oseltamivir is the preferred medication, and the typical duration of treatment should be five days. However, hospitalized patients with severe infections may require longer treatment courses.
  • Treatment should be initiated even before laboratory confirmation of influenza is received, and it should be noted that a negative rapid test for influenza does not rule out the disease. Treatment decisions, especially those involving empiric therapy, should be informed by knowledge of influenza activity in the community.

The CDC said that because of the importance of rapid access to antiviral medications, health care professionals who care for pregnant and postpartum women should develop methods to ensure that treatment can be started quickly after symptom onset. The agency recommended that clinicians

  • inform pregnant and postpartum women about the symptoms of influenza(www.cdc.gov) and the need for immediate evaluation and treatment if symptoms develop,
  • ensure rapid access to telephone consultation and clinical evaluation, and
  • consider empiric treatment based on telephone contact if hospitalization is not indicated and if it will substantially reduce delay before treatment is initiated.

Postexposure antiviral chemoprophylaxis can be considered for pregnant and postpartum women who have had close contact with someone likely to have been infectious with influenza, said the CDC.

Zanamivir may be the preferred antiviral for chemoprophylaxis because of its limited systemic absorption, according to the agency. However, because of the risk of respiratory complications that may be associated with zanamivir's inhaled route of administration, oseltamivir is a reasonable alternative for women at risk for respiratory problems. The duration of postexposure chemoprophylaxis is 10 days after the last known exposure.

Women who are given postexposure chemoprophylaxis should be informed that the chemoprophylaxis lowers -- but does not eliminate -- the risk of influenza and that protection stops when the medication is stopped.


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