Azithromycin

• A macrolide with similar activity to erythromycin but enhanced activity against some Gram negative organisms, particularly Haemophilus influenzae
• Interferes with bacterial protein synthesis
• Oral preparation available
• Has a long tissue half life so once daily dosing is used
• Normal adult dose: 500mg OD for three days. 1g as a single dose for the treatment of uncomplicated genital Chlamydia.
• Hepatic metabolism therefore dose reduction not required in renal failure but avoid in severe liver disease.
• Only use in pregnancy and breastfeeding if no suitable alternative.

Main indications

• Cystic fibrosis/bronchiectasis
• Chlamydia if compliance is a problem
• Prophylaxis for termination of pregnancy
• Restricted agent- above indications only, except with Microbiology approval

Active against most strains of:

• H. influenzae
• Atypical organisms – Chlamydia, mycoplasma, legionella
• S. aureus
• Streptococci (group A, B and S. pneumoniae)

Not active against most strains of:

• Enterococcus sp

• Pseudomonas sp

• Anaerobes

• MRSA

• E.coli

Caution; the antibiotic doses recommended on this website are intended for adult patients with normal renal and liver function unless otherwise stated. Dosing advice for patients with renal impairment is available here.

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