Shift Shown in Influenza A Adamantane Resistance

Abstract

To the Editor: With current concerns about a global influenza pandemic, the study by Dr Bright and colleagues and the accompanying editorial by Drs Weinstock and Zuccotti discussing accelerating adamantane resistance in community-acquired influenza A are alarming. The US Centers for Disease Control and Prevention (CDC) has done an effective job of disseminating this information and instructing clinicians to substitute neuraminidase inhibitors (NIs) as treatment and chemoprophylaxis for influenza this year. However, if overuse of adamantane derivatives has resulted in an increase of resistance in US isolates from 1.9% in 2004 to 92.3% in December 2005, I suggest that we should make every attempt to preserve the efficacy of NIs by using them judiciously and with restraint. While the CDC recommends priority use of influenza antiviral medications for “any person experiencing a potentially life-threatening influenza-related illness” and for “any person at high risk for serious complications of influenza and who is within the first 2 days of illness onset,” it also states that treatment can be considered for “infected adults and children aged 1 year or older who do not have conditions placing them at high risk for serious complications secondary to influenza infection.” This creates a permissive climate in which low-risk patients with nonspecific flulike symptoms may receive multiple courses of antiviral medications in any influenza season, a pattern of treatment likely to accelerate the development of resistance. Influenza is a self-limited illness, and most people outside of high-risk groups require no treatment other than bed rest, fluids, and fever control. Neuraminidase resistance has already been reported. Getting better 1 day faster is not an important enough reason for broad and indiscriminate use of the only remaining effective drugs that are specific against influenza.