Macrolides, tetracyclines, lincosamides and oxazolidinones

At a glance

• All four classes bind the bacterial ribosome. Tetracyclines bind the 30S subunit; macrolides, lincosamides (clindamycin) and oxazolidinones (linezolid) bind the 50S subunit. Most are bacteriostatic.
• Human ribosomes are 80S, which gives selectivity. Mitochondrial ribosomes are bacterial in origin, which explains linezolid's marrow, nerve and lactate toxicity with long courses.
• The examinable adverse effects follow from mechanism: QT prolongation and CYP3A4 inhibition with macrolides, chelation and photosensitivity with tetracyclines, C. difficile with clindamycin, and serotonin toxicity with linezolid.