Last reviewed 2026-04-22 · How we verify

Clarithromycin (ST14)

Clarithromycin inhibits bacterial protein synthesis by binding to the 50S ribosomal subunit, preventing peptide bond formation and bacterial growth.

Clarithromycin inhibits bacterial protein synthesis by binding to the 50S ribosomal subunit, preventing peptide bond formation and bacterial growth. Used for Community-acquired pneumonia, Acute bacterial sinusitis, Acute bacterial exacerbation of chronic bronchitis.

At a glance

Mechanism of action

Clarithromycin is a macrolide antibiotic that binds irreversibly to the bacterial 50S ribosomal subunit, blocking translocation of peptides and halting protein synthesis. This bacteriostatic action prevents bacterial replication and allows the immune system to clear the infection. It is effective against a broad spectrum of gram-positive and some gram-negative bacteria, as well as atypical organisms.

Approved indications

• Community-acquired pneumonia
• Acute bacterial sinusitis
• Acute bacterial exacerbation of chronic bronchitis
• Mycobacterium avium complex (MAC) prophylaxis in HIV patients
• Helicobacter pylori eradication (as part of combination therapy)

Common side effects

• Diarrhea
• Nausea
• Abdominal pain
• Vomiting
• Headache
• QT prolongation
• Hepatotoxicity

Key clinical trials

• Sequential Versus Quadruple Therapy in the Second-line Treatment (PHASE4)

Primary sources

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