Antiplasmodial activity of rifampicin/ sulfadoxine/pyrimethamine combination on Plasmodium berghei infected mice

Introduction: The enormous expense of new medication production and the issue of multidrug opposition by plasmodium parasites has necessitated the exploration on drugs with potential for repurposing. In this study, the antimalarial properties of clinical doses of rifampicin administered with sulfadoxine/pyrimethamine was assessed in Plasmodium berghei contaminated mice.

Materials and Methods: Adult mice (25-30 g) were parasitized with Plasmodium berghei, grouped and treated per oral (p.o) with RIF, SP, and RIF/SP daily. The negative control (NC) and the positive control (PC) were treated daily p.o with normal saline (0.2 mL) and chloroquine (CQ) (10 mg/kg). The 3^rd group of mice received 21.4/1.07 mg/kg body weight of sulfadoxine/pyrimethamine, while the 4^th and 5^th groups were administered 15 mg/kg body weight of rifampicin and 15/21.4/1.07 mg/kg body weight of rifampicin/sulfadoxine/pyrimethamine combination, respectively. Groups I and II received the stated treatments for 3 consecutive days, while group III received a single dose of treatment. Group IV received treatment for 7 consecutive days while group V received a single dose of sulfadoxine/pyrimethamine and the specified dose of rifampicin for 7 consecutive days.

Results: There was significant reduction in parasitemia in all the studies (prophylactic, suppressive, and curative) at the drug doses used: SP (21.4/1.07 mg/kg) (p<0.001), RIF (15mg/kg) (p<0.01), RIF/SP (15/21.4/1.07 mg/kg) (p<0.0001) when compared to the negative control. There was an approximately two and half-fold decrease in percentage parasitemia in the rifampicin/sulfadoxine/pyrimethamine treatment group when compared to the chloroquine treatment group. By the 7th day post-inoculation, Percentage parasitemia in the rifampicin/sulfadoxine/pyrimethamine combination group had reduced to 0.68%.

Conclusion: RIF may be repurposed in combination with SP for malaria treatment.