AZITHROMYCIN

Antibacterial Activity

Effective against bacteria lacking cell wall (eg. mycoplasma, legionella, chlamydia)
Effective against gram-positive aerobes
Effective against gram-negative aerobes except: campylobacter, pasteurella and some H. influenza
Poor anaerobic coverage

Pregnancy Risk Factor

Category B

Contraindication/Precaution

Hypersensitivity to azithromycin or macrolides or any component
Not to used be if concomitant cisapride, terfenadine or astemizole usage
Use caution if impaired liver function

Mechanism of Action

Prevents translocation of polypeptide chain by binding to the P site of the ribosomal 50s subunit

Pharmacodynamics/Kinetics

Metabolism: 
liver
Half-life: 
68 hours, changes with renal function.
Elimination: 
mostly excreted  in feces (bile), and some in urine

Dosage 

Children: 

> 28 days old: 10-12 mg/kg PO day 1, then 5 mg/kg/d

Adults:  

PO: 500 mg day 1 then 250 mg
IV: 500 mg qd

Dosage In Renal Failure

Creatinine clearance (ml/min):
<10: unknown 10-50: unknown 50-80: unchanged >80: unchanged
Dialysis
Hemo: unknown
CAPD: unknown