Antiviral drugs for common respiratory diseases. What's here, what's to come.

Progress is being made in the development of drugs for the prevention and treatment of viral respiratory infections. Two drugs currently available to clinicians are amantadine (Symmetral) and ribavirin (Virazole). Oral amantadine is effective for both treatment and prevention of uncomplicated influenza A infections. Although vaccination continues as the mainstay of influenza prevention, amantadine is useful for unvaccinated patients if complications are likely. When used for treatment, it must be started within the first 48 hours of illness. Ribavirin appears to be safe for treatment of respiratory syncytial virus infections in nonintubated infants. It must be delivered by aerosol in a hospital setting. Patients at risk for complications should be given the drug as early as possible in the course of the disease. Efficacy has yet to be proven in intubated patients, but the drug is probably safe to use with proper supervision. On the horizon are rimantadine and the interferons. Rimantadine is similar to amantadine in its action and indications for use and has a lower incidence of side effects. The interferons have not been the hoped-for panacea for viral respiratory infections but may be useful in a nasal spray for the prevention of colds caused by rhinovirus.