Chemotherapy of respiratory viruses.

We have described positive clinical effects of seven different anti-viral drugs in the treatment of viral respiratory diseases; three of these agents are approved for clinical use--amantadine, acyclovir, and vidarabine. Of the remaining four, the most consistent and broadest range of effect was observed with ribavirin while rimantadine was similar to amantadine in its effect. Interferon and enviroxime, under the conditions in which they were tested, showed a range of effect from moderate to no effect. A feature of the use of ribavirin was its administration by inhalation over several hour periods as a small-particle aerosol. This allowed a total dosage not much less than might have been given by other routes, but with the advantage that it was evenly deposited over the surface of the infected respiratory tract beginning within seconds of the start of treatment and reached higher concentration in nasal secretions than in serum. It may be that aerosol administration can be used with other drugs, as suggested by preliminary results with amantadine. We regard the results presented in this chapter as very encouraging, but just a beginning. Effective therapy will set in motion a reexamination of many problems of viral respiratory tract infection, including how to develop more rapid and more precise viral diagnosis, the need for further characterization of both short- and long-term consequences of infection in the untreated host and their modification by treatment. The structure for rapid progress in treatment of viral diseases is in place, and with it should come a resolution of many long-standing problems in this area of medicine.