Effect of 1-Amantanamine Hydrochloride (Amantadine HCl) and Methyl-1-Adamatanethylamine Hydrochloride (Rimantadine HCl) on Transmission of Influenza Virus Infection in Mice

Abstract

Comparisons were made of the relative effectiveness of amantadine HCl and its analogue rimantadine HCl in protecting mice against influenza A₂/Jap. 305 virus infection. Identical doses of the 2 compounds were injected intraperitoneally prior to exposure to an artificial aerosol of virus or to influenza virus infection transmitted by other mice. Amantadine HC1 had virtually no effect in these studies in suppressing pulmonary virus titers, preventing lung lesions, or in decreasing the likelihood of acquisition of infection transmitted by other mice. In contrast, intraperitoneal injection of rimantadine resulted in lower pulmonary virus titers, less severe lung lesions, and decreased antibody response following challenge with 100 MID/50 of A₂/Jap. 305 virus, and rimantadine treated mice were less capable of transmitting infection to contact animals than amantadine treated or control infector mice. Furthermore, rimantadine treatment increased the quantity of aerosolized virus needed to initiate infection and resulted in a decreased susceptibility to the acquisition of influenza virus infection transmitted by other mice.