A patient with community-acquired pneumonia is prescribed azithromycin. What is its mechanism of action?
- A Binds 50S subunit and blocks translocation ✓
- B Binds 30S subunit and inhibits initiation
- C Inhibits peptidoglycan cross-linking
- D Inhibits dihydrofolate reductase
Correct answer: A. Binds 50S subunit and blocks translocation
Explanation
Macrolides like azithromycin bind to the 23S rRNA of the 50S ribosomal subunit, blocking the translocation step of protein synthesis. They do not bind 30S or inhibit cell wall synthesis. Azithromycin also has immunomodulatory effects in chronic lung diseases.
Reference: Katzung: Basic & Clinical Pharmacology, 14th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.