Adriamycin inhibits Ca permeability and Ca-dependent K movements in red blood cells.

Normal human red blood cells show a prompt, large increase in K permeability when their cytoplasmic Ca concentration is increased by various in vitro manipulations. Adriamycin, in concentrations greater than 0.02 mM, inhibits this response. Although the mechanism of adriamycin's action is not clear, experiments with dog red blood cells suggest that the drug inhibits passive Ca permeability. The importance of Ca-gated K movements in red blood cells is obscure, but in excitable tissues such ion currents play an important role in membrane repolarization. The influence of adriamycin on this ion conductance pathway may be related to the acute cardiotoxic and neurotoxic effects of the drug.