Interaction between aromatic diamidines and nucleic acids: possible implications for chemotherapy

Interaction between aromatic diamidines (pentamidine, propamidine, and stilbamidine) and nucleic acids were studied to elucidate the mechanism underlying renal toxicity induced by pentamidine in patients. Pentamidine, propamidine, and stilbamidine precipitated with RNA and DNA of all species and types. Furthermore, the diamidines interacted and precipitated with all nucleoside triphosphates and nucleoside diphosphates, but not with nucleoside monophosphates, nucleosides, or free bases. Nucleoside diphosphate is the minimum unit necessary for interaction with the diamidines. This interaction between diamidines and nucleotides or nucleic acids may be implicated in the etiology of renal damage and skin reactions associated with these drugs.