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
2. Anaerobes
3. Obligate intracellular organisms (legionella, mycoplasma)
4. Gram negatives including Moraxella, Neisseria, H. Influenzae

Adverse Effects Toxicity

1. Nausea, vomiting, diarrhea
2. Hypersensitivity
3. Less QT prolongation
4. Inhibits CYP3A4 (increased warfarin, carbamazepine, ciclosporin, valproate, tacrolimus, digoxin)
Inhibits P-glycoprotein

Absorption

37% oral absorption

Distribution

Poor CSF penetration but good lung penetration

Protein binding

12-50% PB

Volume of distribution

Vd 0.5L/kg

Metabolism

Hepatic metabolism to inactive metabolites

Excretion

Major route of excretion is bile
12% unchanged in the urine

Half-life

T1/2 of 68 hours