The combination of carvacrol and albendazole enhanced the efficacy of monotherapy in experimental alveolar echinococcosis.

Alveolar echinococcosis is a helminthic zoonosis caused by the larval stage of Echinococcus multilocularis. When surgical resection of the parasite is not feasible, pharmacological treatment with albendazole is the only option. Due to the difficulties in achieving the success of treatment, it is necessary to find new drugs to improve the treatment of this disease. In the present work, the efficacy of carvacrol alone or combined with albendazole was evaluated against E. multilocularis metacestodes. The association of carvacrol with albendazole produced a greater in vitro effect than the compounds incubated separately. The most effective treatment was the combination of 10 μg/ml of carvacrol and 1 μg/ml of albendazole. In the clinical efficacy study, treatment of infected mice with carvacrol (40 mg/kg) and albendazole (25 mg/kg) reduced the weight of metacestodes by 29 % and 50 %, respectively; while the combination of drugs had an efficacy of 83 %. These results coincided with the tissue damage observed at the ultrastructural level. In conclusion, carvacrol and albendazole combination enhanced the efficacy of monotherapy. This strategy would allow to improve the efficacy of the treatment without increasing the doses of albendazole or lengthen the treatment period, reducing the occurrence of adverse effects.