The effect of pentamidine salts on the respiratory burst of human neutrophilic granulocytes.

Therapeutic concentrations (0.3-1.5 mg/l) of pentamidine isethionate and pentamidine mesylate, obtained after parenteral administration of either drug, did not affect oxygen consumption in the stimulated neutrophilic granulocyte. At concentrations of 0.7, 1.1 and 1.5 mg/l, superoxide production, hydrogen peroxide production, myeloperoxidase (MPO)-mediated iodination and hexose monophosphate shunt activity were suppressed relative to untreated cells (P less than 0.001 in each case). The depression in each activity was dose-related. There was no significant difference between the drugs with regard to these impairments in neutrophilic granulocyte function. This lowered respiratory burst activity, which would lead to a depression of MPO-dependent and MPO-independent processes in stimulated neutrophilic granulocytes, may be due to drug induced dysfunction of NADPH-oxidase.