The polyene antibiotic amphotericin B inhibits the Na+/K+ pump of human erythrocytes.

The polyene antibiotic Amphotericin B is known to induce K+ loss from human erythrocytes. In the present study it is shown that this efflux is not solely due to the formation of pores through the membrane but also to the inhibition of the Na+/K+ pump. At 5 microM this inhibition is total. The interaction of Amphotericin B with membrane enzymes is therefore to be taken into consideration when trying to explain its mechanism of action.