Adrenocortical insufficiency in Rhodesian sleeping sickness is not attributable to suramin

Suramin, a polysulphonated naphthylurea used in the treatment of human African trypanosomiasis (HAT), is known to cause adrenocortical insufficiency in doses exceeding the quantity used for treatment of HAT. We have previously reported that Trypanosoma brucei rhodesinese infection causes a combined central and peripheral adrenal insufficiency. To evaluate whether suramin therapy acts as an additional adrenotoxic factor, we assessed adrenocortical function in 72 patients suffering from HAT at different times during treatment with either suramin or melarsoprol by a rapid adrenocorticotropic hormone test. We found a significantly diminished peak cortisol response to stimulation in the acutely ill patients (P = 0.001), indicating impaired adrenocortical function, as well as a high incidence of partial adrenocortical insufficiency (27%). During and after trypanocidal therapy the incidence of partial adrenal insufficiency gradually declined (to 25% and 18% respectively). Stimulated peak cortisol levels did not differ significantly between patients receiving suramin and those given melarsoprol. No correlation was found between serum suramin concentration and the cortisol response to stimulation (r = 0.09, P = 0.47). Thus we conclude that suramin in trypanocidal doses neither causes nor worsens the adrenocortical dysfunction observed in Rhodesian HAT.