A patient receiving polymyxin B sulfate intravenously for Gram-negative bacteremia developed progressive hyperchloremia and a negative "anion gap." Both abnormalities resolved following discontinuation of the drug. In vitro investigation suggested that the electrolyte abnormalities resulted from the polycationic properties of polymyxin B.
(Arch Intern Med 138:478-480, 1978)
O'Connor DT, Stone RA. Hyperchloremia and Negative Anion Gap Associated With Polymyxin B Administration. Arch Intern Med. 1978;138(3):478-480. doi:10.1001/archinte.1978.03630270086029