Trypanocidal

Trypanocidal is an adjective describing substances that kill trypanosomes, the flagellate protozoa of the genus Trypanosoma. In medicine, trypanocidal agents are used to treat infections caused by T. brucei species that cause African trypanosomiasis (sleeping sickness) and T. cruzi, which causes American trypanosomiasis (Chagas disease).

Some agents are trypanocidal, others are trypanostatic. The stage of infection matters: many drugs clear bloodborne parasites but do not reach the central nervous system, whereas late-stage disease with CNS involvement requires agents that cross the blood-brain barrier.

Common trypanocidal drugs include suramin and pentamidine for early African trypanosomiasis; melarsoprol and eflornithine (often used with nifurtimox in NECT therapy) for infections that have invaded the CNS. For Chagas disease, benznidazole and nifurtimox are used. In veterinary medicine, diminazene aceturate, isometamidium, and homidium are widely employed; human use is limited or restricted in some regions due to toxicity.

Mechanisms vary: eflornithine inhibits ornithine decarboxylase, depleting polyamines; other drugs act as prodrugs producing toxic intermediates or disrupting DNA replication. The selectivity for parasites over host cells reduces some toxicity, but many trypanocides have serious adverse effects.

Clinical use faces challenges including toxicity, resistance, and variable efficacy by species and disease stage. Access to safe, effective treatments remains uneven in endemic areas, and ongoing research seeks new agents with improved safety profiles and ability to treat CNS infections.