Introduction:

Amphotericin B is an effective drug for the treatment of the different clinical forms of leishmaniasis. However, there are reports of its ineffectiveness in animals experimentally infected withLeishmaniaspp. That is why, the objective of the present work was to evaluate the balance of activity-toxicity at amphotericin B doses over 1 mg/kg, so that its use as a positive control antileishmanial drug were adequate.

Method:

BALB/c mice were experimentally infected withL. amazonensisand treated with amphotericin B by intraperitoneal route at doses from 5 mg/kg to 12.5 mg/kg, beginning 21 days after infection. The size of the lesions and the body weight of the mice were measured for eleven weeks after the commencement of treatment. The number of parasites was also determined three days after the end of treatment.

Results:

Amphotericin B at 5 mg/kg retarded lesions growth but neither reduced lesion size nor the parasite load at lesion site. Doses of 7.5 mg/kg to 10 mg/kg, every 48 h for 14 days (7 doses) caused a significant reduction of lesion size and parasite load without evident loss of body weight and without signs of toxicity. Amphotericin B at 12.5 mg/kg was more effective but produced unacceptable toxicity.

Conclusions:

The results support the use of amphotericin B as a positive control drug in BALB/c mice experimentally infected withL. amazonensisat doses of 7.5 mg/kg to 10 mg/kg to achieve an effect comparable to that observed in clinical practice.

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