Flashcards in 8.4 Deck (14):
Which drugs are in the category Macrolides? (4)
What is the MOA of Macrolides?
Reversibly bind to the 50S subunit inhibiting translocation.
How do Macrolides gain resistance? (3)
3 main mechanisms (usually plasmid encoded):
• Reduced membrane permeability or active efflux
• Production of esterase that hydrolyze drugs (by
• Modification of ribosomal binding site (by chromosomal mutation or by a methylase)
Macrolides are effective against which bacteria?
Most active against Gram-positive bacteria (some activity against Gram-negatives)
What is the DOC for Mycoplasma Pneumoniae?
Macrolides (along with tetracyclines)
Macrolides more safe in pregnancy.
What is the DOC for whooping cough?
What is the clinical applications for macrolides?
- Used in empiric therapy of community-acquired
pneumonia (outpatient & in combination with B-lactam for inpatients)
- Treatment of upper respiratory tract & soft-tissue infections (eg, Staph, H.influenzae, S.pneumoniae,
What is important to know about the PK of Erythromycin, clarithromycin & telithromycin?
CYP P450 inhibition (NOT azithromycin)
What are the adverse effects of Macrolides?
• GI irritation
• Hepatic abnormalities (erythromycin & azithromycin)
• QT prolongation
• Severe reactions are rare (anaphylaxis, colitis)
What are the contraindications for Macrolides?
• Statins (due to macrolides inhibiting CYP P450)
• Telithromycin – fatal hepatotoxicity, exacerbations of
myasthenia gravis, & visual disturbances don’t use for
What is the MOA of Chloramphenicol?
• Enters cells via active transport process
• Binds reversibly to 50S ribosomal subunit (site adjacent to site of action of macrolides & clindamycin)
How does Chloramphenicol cause bone marrow toxicity?
Can inhibit protein synthesis in mitochondrial ribosomes
Chloramphenicol inhibits which cytochrome enzymes?