Amiodarone and Ravuconazole Combination Potentiates Chemotherapy against Drug-Resistant <i>Trypanosoma cruzi</i> Strains

Drug combinations represent valuable opportunities for developing more effective and safer treatments for Chagas disease. In this study, we investigated the effects of ravuconazole and amiodarone combinations against Trypanosoma cruzi infection. After ruling out antagonistic effects and increased cytotoxicity in vitro, a short-term in vivo protocol was used to evaluate parasitemia, immune response, and heart damage caused by the Y and Colombian T. cruzi strains in BALB/c and Swiss mice. Untreated mice displayed elevated parasitemia and pro-inflammatory cytokine levels, with strain-specific differences in IL-10 levels and the presence of parasites in the myocardium. Amiodarone monotherapy failed to exhibit in vivo anti-T. cruzi activity. While ravuconazole monotherapy at a subtherapeutic dose reduced parasitemia in all treated animals, its effects on the host response varied depending on the mouse and parasite strain, demonstrating greater activity in Swiss mice infected with the Y strain. Remarkably, amiodarone enhanced ravuconazole efficacy as combination chemotherapy was more effective than monotherapy in downregulating parasite load and pro-inflammatory cytokine levels, attenuating cardiac damage in all experimental models. These findings demonstrate a positive in vivo interaction between ravuconazole and amiodarone against T. cruzi infection. Furthermore, they highlight the relevance of the host genetic background and parasite strain on treatment outcomes.