Abstract

Two antimalarial drugs; Halofantrine HCl and Artemether whose mechanism of action has been shown to depend on the disruption of the red blood cells during malarial infections were investigated for possible trypanocidal activity in vivo. Pre-treatment with Artemether before infection with the parasite had no effect on infected rat when compared to the control. Treatment at the early stage of infection extended the lifespan from 11 days for control to 13^th and 14^th days post infection for dose treatments at 4.6 and 2.3 mg/kg rat weight respectively. Similar results were obtained for late stage treatment. Pre-treatment with Halofantrine HCl extended the life span to 16 days at 7.1 mg/kg rat weight. Early stage treatment with 7.1 and 14.2 mg/kg rat weight extended life span to 14 and 13 days respectively even though parasitaemia kept decreasing until death of the animals. The late stage treatment however extended the life span to 18 days. A combination of both drugs maintained low parasitaemia and extended life span to 16 days for prophylactic treatment, 15 and 16 days for early stage treatment at 2.3 mg Artemether and 7.1 mg/Kg Halofantrine HCl; 4.6 and 14.2 mg/Kg rat weight respectively, and 19 days for late stage treatment. Results suggest that Halofantrine HCl and possibly Artemether could be useful in the management of trypanosomosis since both drugs were able to maintain low parasitaemia. Parasitaemia has been shown to correlates with the severity of infection.

Key words: Halofantrine, artemether, parasitaemia,  trypanosomosis, red blood cells.