THE CHEMOTHERAPY OF ONCHOCERCIASIS .18. ASPECTS OF TREATMENT WITH SURAMIN

We report the clinical and parasitological effects of a modified treat ment regimen for suramin. Twenty adult males received up to 5 g (72.5 to 84.7 mg/kg) of suramin over 36 days. Detailed clinical and laborato ry examinations were done before treatment and then at intervals over 2 years. Nodules were removed at 6, 13, 26 and 52 weeks for histology. Systemic tolerance was good. Anterior segment inflammation was howeve r common and 2 patients required intervention to prevent posterior syn echiae. No new posterior segment lesions developed; a rare improvement occurred in one patient with papillitis. Proteinuria, mostly mild, oc curred in nearly all patients. Previously unreported renal glycosuria was documented in one patient. Microfilariae in the skin and anterior chamber did not change significantly for 5 or more weeks after which r apid reductions occurred. Ocular parasites were absent at 2 years and skin microfilariae were near zero. Peripheral blood eosinophil counts fell in parallel with those of microfilariae in the skin and anterior chamber and were normal at one and two years. These findings at 2 year s may provide indirect evidence of a macrofilaricidal or a permanent c hemosterilant effect on the adult worms. Nodule examination revealed a n embryotoxic effect from week 6, a lethal effect on the male worms fr om month 3 and on the female worms from month 6 after treatment starte d. At one year 34 % of the female worms examined were alive. Thus tota l doses of suramin in the range 72.5 to 84.7 mg/kg have only a modest lethal effect on the female worms. Suramin remains a restricted drug a nd a suitable replacement is needed.