About Erythromycin Macrolide Antibiotic. Mechanism of Action of Erythromycin Erythromycin is a member of macrolide antibiotics. It binds to the 50S sub unit of bacterial ribosome and inhibits translocation.ie: they interfere with the transfer of the newly formed peptide chain from the A site to the P site and fails to expose the A site .So that A site is unable to bind with the next aminoacyl t RNA complex. This leads to premature termination of amino acid chain and there by inhibits protein synthesis. Interactions for Erythromycin Anticoagulants: Efficacy enhanced leading to haemorrhages. Bromocriptine: Efficacy protentiated leading to toxicity. Carbamazepine: Dangerous toxic side effects requiring resuscitative measures and hospitalisation. Digoxin: Serum levels of digoxin enhanced, leading to toxicity. Disopyramide: Increased disopyramide plasma levels leading to arrhythmias. Ergot Alkaloids: Acute ergotism manifested as peripheral ischaemia.