August 22, 2012

CDC Offers Guidance on Effective Swine Flu Treatment

AtlantaA large increase in cases of H3N2v swine flu virus has occurred this year, and the CDC has issued interim information for health care professionals on treating the illness.

The strain of influenza was first detected in the U.S. in a human case in 2011, the CDC notes, although the virus appears to be widely circulating in swine here. Most of the cases have been in children and have been linked to direct or indirect exposure to pigs, especially at agricultural fairs.

No deaths have occurred, and only a few patients have been hospitalized.

The CDC suggests that patients with uncomplicated H3N2v virus infection be managed on an outpatient basis with OTC symptom relief. However, early neuraminidase inhibitor antiviral treatment is recommended for all patients suspected of being infected who also are either hospitalized, have severe or progressive illness, or fall into high-risk groups such as the very young, the very old, or pregnant women. Treatment should be initiated even before lab results are available, the CDC emphasizes.

H3N2v viruses tested to date are susceptible to the neuraminidase inhibitor drugs oseltamivir and zanamivir but resistant to the antiviral drugs amantadine and rimantadine, according to the CDC. Federal health officials do not recommend antiviral chemoprophylaxis, pre- or postexposure, instead saying that high-risk individuals who become ill should seek medical care and then receive early antiviral treatment.

Also not recommended are systemic corticosteroids for patients with suspected or confirmed influenza, including H3N2v virus infection, except in cases where patients are already using the drugs to treat chronic conditions such as asthma.

The CDC also reminds pharmacists and other health care professionals to caution parents against using aspirin or aspirin-containing products to relieve discomfort in children with influenza or influenza-like illnesses because of the risk of Reye's syndrome.

One complication in choosing an appropriate therapy is that H3N2v virus infection can't be distinguished by clinical features from seasonal influenza A or B virus infection, or from infection with other respiratory viruses that can cause influenza-like illness. Instead, clinicians are urged to inquire whether their patients had any direct contact with pigs, such as raising them, feeding them, or cleaning up their waste; whether the patient has recently visited a pig farm or walked through a swine barn, especially if the pigs were ill; or had close contact (been within 6 feet of) someone with recent swine exposure.

This year's influenza vaccine offers no specific protection against the swine flu virus, the CDC notes.

U.S. Pharmacist Social Connect