Efficacy of topical hydrophilic gel of paromomycin combined with systemic or locally administered leishmanicidal drugs for treatment of experimental leishmaniasis caused by Leishmania (Viannia) braziliensis.

Objective: This study aimed at evaluating the combination of a topical hydrophilic gel of paromomycin (PA) with intralesion meglumine antimoniate (Glu IL) or systemic administration of liposomal amphotericin B (AmphLipo) for the treatment of cutaneous leishmaniasis caused by Leishmania (Viannia) braziliensis.

Materials and methods: Initially, to guide the subsequent evaluation of binary combinations, in vivo studies were conducted to evaluate the different therapeutic regimens in monotherapy: PA, twice a day for 30 consecutive days, AmphLipo, single dose or five doses (both with a total dose of 10 mg/kg) and Glu IL, single lesion infiltration (weekly or biweekly). Clinical efficacy was evaluated by measuring the size of the lesion and parasitological efficacy by limited dilution assay of the parasite culture.

Results: PA showed a tendency to reduce the size of the lesion, but without a significant difference in relation to the control. AmphLipo reduced the parasite load in the spleen (P < 0.05), but there was no difference in the size of the lesion between the treated groups and the control group. Glu IL showed complete epithelialization in 80% (weekly) and 100% (fortnightly) of the animals (P < 0.05) but did not reduce the parasite load. Instead, all binary combinations (PA + GluIL, PA + AmphLipo and GluIL + AmphLipo) reduced the size of the lesions by 100% (P < 0.05). No animal showed weight loss or toxic effects, such as ruffled fur, aggressiveness, diarrhoea or other adverse reactions.

Conclusions: The combinations tested were more effective in healing the lesions than the monotherapies, representing a promising alternative for the treatment of cutaneous leishmaniasis and encouraging new clinical trials.