Evaluation of the safety of amantadine-HC1 and the role of respiratory viral infections in children with cystic fibrosis.

Amantadine-HC1, an antiviral drug clinically effective against most strains of influenza A virus, was evaluated in a double-blind trial in 153 children with cystic fibrosis during the initial appearance of influenza A/England/42 virus in the New England area. Infection with this variant strain of influenza virus did not reach epidemic proportions during the study, so that the effectiveness of amantadine in this study population could not be fully assessed. However, the potential symptomatic and biochemical toxicity of amantadine was carefully monitored in a pediatric population. Serologic screening by complement fixation tests indicated that respiratory viruses may be important pathogens in exacerbations of respiratory disease in patients with cystic fibrosis.