PHARMACOLOGY OF EXISTING DRUGS FOR ANIMAL TRYPANOSOMIASIS

Lack of much interest by the pharmaceutical industry to venture into d evelopment of new antitrypanosomal drugs has been a major stimulus to an intensification of research into the few existing drugs. Those indi cated for animal trypanosomiasis include: isometamidium, homidium and diminazene, used primarily against Trypanosoma congolense, T. vivax an d T. brucei; and quinapyramine, mainly indicated for use against T. ev ansi infections. A great deal of research effort has focused on develo pment of pharmacological and parasitological methodologies, which have considerably advanced our understanding on the efficacy, resistance, disposition and toxicological mechanisms of these drugs. While a clini cal breakthrough has been made in the recent past, in the field of che motherapy of T. evansi infections by the introduction of a new arsenic compound, melarsenoxide cysteamine, chemotherapy of T. simiae infecti ons in pigs still remains a major challenge because the existing drugs are either ineffective or too toxic for economic use. Further researc h into the existing drugs is a prerequisite for their optimal usage in the overall effort of improving animal health and productivity throug h control of trypanosomiasis.