Influenza

In otherwise healthy children and adults with uncomplicated influenza infection, antiviral therapy is not generally warranted. Bed rest, adequate fluid intake, and treatment with analgesics, cough suppressants, and decongestants may improve symptoms. In patients at significant risk for the development of complications of influenza, or in those with influenza pneumonia, the use of antiviral medications may decrease morbidity and mortality. Until recently, therapy for influenza typically involved the use of amantadine or rimantadine, antiviral drugs active against influenza A. Most studies examining the efficacy of these drugs have shown a reduction in clinical symptom scores, a faster resolution of fever, and a decrease in the level and duration of infectivity. Most authorities support the use of amantadine in the treatment of complicated influenza A virus infection, even late in the course of illness. Treatment with antiviral medications is also generally recommended for outbreaks of influenza A virus infection in LTCFs, although whether these drugs prevent illness, relieve symptoms, or reduce the duration of illness or complications in this setting is not clear.

These drugs can lead to complications. Confusion, delerium, seizures, falls, insomnia, or fractures occur in 22 to 47 percent of residents of LTCFs treated with amantidine, and drug resistance develops readily. Side effects can be reduced in the elderly by reducing the dose of amantadine to 100 mg or less daily in the presence of renal insufficiency. Central nervous system side effects are less problematic with rimantadine than with amantadine.

The neuraminidase inhibitors are a new class of antiviral medications with activity against both influenza A and B virus. These agents, although expensive, offer a much better side-effect profile and are better tolerated in the elderly than amantadine. Although resistance to these agents has been reported, it is not yet a significant problem. The role of these agents in the prevention and treatment of influenza infections in the elderly has not yet been established, but there is mounting evidence to suggest that they may play a key role in the management of influenza in LTCFs in the near future.