Core pharmacology

Class Group

ANTIBIOTIC:
MACROLIDE

Legacy Cicm Level

Level 3

Presentation

PO, IV

Mechanism of action

Inhibits 50s subunit to prevent protein synthesis
Bacteriocidal/static

Antimicrobial Spectrum

1. Gram positives (better strep and listeria cover)
2. Anaerobes
3. Obligate intracellular organisms (legionella, mycoplasma)
4. Gram negatives- including Helicobacter

Adverse Effects Toxicity

1. Nausea, vomiting, diarrhea
2. Hypersensitivity
3. QT prolongation and increased risk of torsade’s
4. Inhibits CYP3A4 (increased warfarin, carbamazepine, ciclosporin, valproate, tacrolimus, digoxin)
Inhibits P-glycoprotein

Absorption

50% absorption

Distribution

Poor CSF penetration but good lung penetration

Protein binding

8% PB

Metabolism

Hepatic metabolism via N-dealkalylation

Excretion

Renally excreted (33% unchanged)
10% in bile

Half-life

T1/2= 5-6 hours