Amantadine effect on peripheral airways abnormalities in influenza. A study in 15 students with natural influenza A infection.

Amantadine HCl administration has resulted in accelerated resolution of influenza A illness. Prolonged abnormalities in pulmonary function have been described in uncomplicated influenza A. To study the effect of amantadine on these changes, we evaluated young adults with documented natural influenza A with clear chest examinations and X rays. Subjects received placebo or amantadine in random, double-blind fashion. Physiologic studies included maximal expiratory flow volume curves with air and helium-oxygen mixtures. Air flow rates were unchanged in all subjects throughout. Initially, both groups showed comparable decreases in mean helium-oxygen maximal expiratory flow rates. The amantadine group showed accelerated physiologic improvement: significant increase in helium-oxygen flow rates occurred within 7 days (P less than 0.05). The rate of improvement in the helium-oxygen flow rates in the placebo group was not statistically significant. These studies confirm peripheral airways dysfunction after uncomplicated influenza A and suggest that amantadine is associated with accelerated resolution of this dysfunction.