In-vitro antiviral activity of doxepin hydrochloride against group B coxsackievirus.

Group B coxsackievirus is an enterovirus that can cause a variety of diseases, including myocarditis, aseptic meningitis, and hand, foot, and mouth disease. Currently, there is no effective antiviral drug against this virus. In this study, we used a cytopathic effect-based viral inhibition assay to screen an FDA-approved drug library and found that doxepin hydrochloride had potential antiviral activity. Doxepin hydrochloride exhibited strong antiviral activity against coxsackievirus B types 1-3 with a 50% inhibitory concentration of 10.12 ± 0.85 μM. Moreover, doxepin hydrochloride did not exert antiviral activity against other enteroviruses, including enterovirus A71 (subtypes BrCr/C4) and coxsackievirus A (subtypes 6/10/16). Furthermore, doxepin hydrochloride inhibited virus replication in the early stage of the infection cycle rather than affecting the entry or assembly process. In addition, a few mechanism-related pharmacophores were discovered through gene association network analysis. These findings identify a possible lead compound for treating coxsackievirus B infection and simultaneously offer valuable clues for drug repositioning.