What are examples of macrolide (macrolide antibiotics) medications?

Macrolide Antibiotics

The macrolide class includes erythromycin, azithromycin, and clarithromycin as the three primary drugs available in North America, with azithromycin technically classified as an azalide (a closely related 15-membered ring compound). 1

Core Macrolide Medications

14-Membered Ring Macrolides

• Erythromycin - the first macrolide antibiotic, launched commercially in 1952, remains the least expensive but is less commonly used due to gastrointestinal intolerance and lack of activity against H. influenzae 1
• Clarithromycin - a newer 14-membered macrolide with improved tolerability and broader spectrum than erythromycin 1
• Roxithromycin - another 14-membered macrolide available in some countries 1, 2

15-Membered Ring Macrolides (Azalides)

• Azithromycin - technically an azalide (closely related to macrolides), became available in the 1980s with superior activity against H. influenzae and improved pharmacokinetics allowing once-daily dosing 1

Additional Macrolides

• Dirithromycin - a macrolide with very long half-life, studied primarily outside North America 2, 3

Mechanism of Action

All macrolides share a common mechanism: they reversibly bind to the 23S rRNA component of the 50S bacterial ribosomal subunit, specifically at the polypeptide exit region, thereby inhibiting RNA-dependent protein synthesis. 1, 2 While generally bacteriostatic, macrolides demonstrate bactericidal activity against autolytic species such as pneumococci. 1

Key Structural Features

Macrolides are defined by their macrocyclic lactone ring containing 12 or more elements, with the most commonly used antibiotics having either 14-membered rings (erythromycin, clarithromycin) or 15-membered rings (azithromycin). 1, 4

Clinical Considerations

The CDC recommends macrolides (erythromycin, clarithromycin, or azithromycin) as preferred agents for treatment of pertussis in persons aged >1 month, with azithromycin specifically preferred for infants <1 month. 1 For community-acquired pneumonia, macrolides are recommended as monotherapy for previously healthy outpatients or in combination with β-lactams for hospitalized patients. 1

Important Distinctions

• Lincomycin is NOT a macrolide - it belongs to the lincosamide class, which is structurally different despite sharing the same ribosomal binding site and cross-resistance patterns with macrolides 4
• Telithromycin - represents a newer ketolide class (modified 14-membered macrolides with a 3-keto group replacing the L-cladinose moiety), though it has limited use due to safety concerns 5, 6