Rimantadine microbiology
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Microbiology
Rimantadine is inhibitory to the in vitro replication of influenza A virus isolates from each of the three antigenic subtypes, i.e., H1N1, H2N2 and H3N2, that have been isolated from man. Rimantadine has little or no activity against influenza B virus (Ref. 1,2). Rimantadine does not appear to interfere with the immunogenicity of inactivated influenza A vaccine.
A quantitative relationship between the in vitro susceptibility of influenza A virus to rimantadine and clinical response to therapy has not been established.
Susceptibility test results, expressed as the concentration of the drug required to inhibit virus replication by 50% or more in a cell culture system, vary greatly (from 4 ng/mL to 20 μg/mL) depending upon the assay protocol used, size of the virus inoculum, isolates of the influenza A virus strains tested, and the cell types used (Ref. 2).
Rimantadine-resistant strains of influenza A virus have emerged among freshly isolated epidemic strains in closed settings where rimantadine has been used. Resistant viruses have been shown to be transmissible and to cause typical influenza illness. (Ref. 3)[1]
References
Adapted from the FDA Package Insert.