The Centers for Disease Control and Prevention (CDC) announced this week that this season’s predominant strain of influenza (H3N2) is highly resistant to amantadine and rimantadine, two common antiviral medications. CDC urges physicians not to prescribe these antivirals to treat or prevent influenza during the 2005-2006 influenza season.

CDC recommends physicians instead prescribe oseltamivir (Tamiflu) or zanamivir (Relenza) if an antiviral medication is needed for the treatment of influenza. These newer drugs are more effective and have fewer side effects, and seasonal flu viruses have not yet developed resistance to either of these drugs.

Antivirals should primarily be used to treat patients hospitalized with flu symptoms and to prevent the flu in group situations, such as nursing homes, where the virus can easily spread. Physicians are reminded that inappropriate prescribing and use of antivirals will lead to antiviral resistance among influenza viruses.

Influenza activity is starting to pick up across the country, with widespread flu activity in the western and southwestern states, including California, Arizona, Colorado, Nevada, New Mexico, Texas, and Utah. Physicians are encouraged to continue vaccination efforts throughout the season, especially among health care workers, individuals with medical conditions that put them at an increased risk of influenza-related complications, and those over age 65. This year’s flu virus will continue to circulate for several more months.

CDC recently authorized Sanofi Pasteur to sell its stockpile of flu vaccine to physicians and others. To encourage continued vaccination efforts, and to minimize financial risk to physicians, the vaccine is being sold with a return policy. Physicians will be able to return unused vaccine within 30 days for a credit.

Flu vaccine is also available from some vaccine distributors, including FFF Enterprise (nonreturnable) and McKesson Corporation (returnable). Some physicians who have extra vaccine for sale have also contacted CMA.

Contact: Robin Flagg, 415/882-5110 or rflagg@cmanet.org.