Comparison of the antiviral activity in vitro of some non-steroidal anti-inflammatory drugs.

In cultures of mouse or chick embryo ceils several non-steroidal antiinflammatory drugs (salicylates, Ibufenac, phenylbutazone, Indomethacin, flufenamic and mefenamic acids, CI-583, and chloroquine) inhibit the multiplication of various viruses (encephalomyocarditis, Sindbis, influenza A2, Newcastle disease, herpes simplex and vaccinia). Two factors were critical for the virus inhibitory action of these drugs: the concentration of serum and the pH of the medium. The antiviral effect of these drugs seems to be due mainly to limitation of intraceUular synthesis. However, salicylates and anthranilates also inhibit the adsorption and/or penetration of encephalomyocarditis virus into mouse cells. The antiviral potency shows some correlation with other biochemical, cellular and clinical activities of these drugs.