Repurposing antipsychotic drugs into antifungal agents: Synergistic combinations of azoles and bromperidol derivatives in the treatment of various fungal infections.

As the number of hospitalized and immunocompromised patients continues to rise, invasive fungal infections, such as invasive candidiasis and aspergillosis, threaten the life of millions of patients every year. The azole antifungals are currently the most prescribed drugs clinically that display broad-spectrum antifungal activity and excellent oral bioavailability. Yet, the azole antifungals have their own limitations and are unable to meet the challenges associated with increasing fungal infections and the accompanied development of resistance against azoles. Exploring combination therapy that involves the current azoles and another drug has been shown to be a promising strategy. Haloperidol and its derivative, bromperidol, were originally discovered as antipsychotics. Herein, we synthesize and report a series of bromperidol derivatives and their synergistic antifungal interactions in combination with a variety of current azole antifungals against a wide panel of fungal pathogens. We further select two representative combinations and confirm the antifungal synergy by performing time-kill assays. Furthermore, we evaluate the ability of selected combinations to destroy fungal biofilm. Finally, we perform mammalian cytotoxicity assays with the representative combinations against three mammalian cell lines.