Erythromycin

Uses: respiratory, skin, oral infections; impetigo; diabetic foot infection
Also prokinetic
Spectrum Gram +ve and -ve - including MRCEM pathology/Microbiology/Mycoplasma pneumonia and Legionella pneumonia
Mechanisms of resistance - efflux mechanisms
- methylation of ribosomal binding site
Mechanism of action Inhibits bacterial protein synthesis by inhibiting translocation of tRNA - binds to 50S ribosomal subunit
Bacteriostatic and bacteriocidal
Dose typically 250-500mg QDS
Pharmacokinetics Absorption PO, IV
Distribution poor CSF penetrance
Metabolism liver
Elimination urine. t½ 1.5h
Time course of action
Adverse effects haemolytic anaemia
GI upset - prokinetic
Pancreatitis
QT prolongation

Important drug interactions:
- P450 inhibitor (i.e. ↓ clearance in drugs metabolised by P450) - i.e. ↑ warfarin effect
- ↑ effect of statins