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Macrolide Antibiotic — Bacterial Conjunctivitis / Trachoma / Blepharitis Pregnancy: Topical: considered low risk; oral: generally considered safe — used in trachoma mass treatment programmes including pregnant women

Azithromycin 1.5% Eye Drops

Brand names: AzaSite, Azithrocin Eye

Adult dose

Dose: Bacterial conjunctivitis: 1 drop twice daily for 2 days then once daily for 5 days; Trachoma (systemic): azithromycin 20 mg/kg oral single dose (max 1 g) — NOT topical for trachoma
Route: Topical ophthalmic (drops); oral for systemic trachoma treatment
Frequency: Twice daily days 1–2; once daily days 3–7
Max: 1 drop per dose
Novel dosing regimen — fewer drops per day than fluoroquinolones; penetrates biofilm well; systemic azithromycin is WHO-recommended mass treatment for trachoma (SAFE strategy); oral azithromycin 500 mg OD for 3 days also used for ocular rosacea/blepharitis

Paediatric dose

Dose: 20 mg/kg
Route: Oral (systemic trachoma) or topical (conjunctivitis)
Frequency: Single dose (trachoma); twice then once daily (topical)
Max: 1 g oral; 1 drop topical per dose
Oral azithromycin 20 mg/kg (max 1 g) is WHO first-line for trachoma in children; topical: licensed from 1 year (oral — trachoma)

Dose adjustments

Renal

No adjustment required for topical use; oral: no adjustment for trachoma single dose

Hepatic

Use with caution if significant hepatic impairment (oral); no adjustment for topical

Paediatric weight-based calculator

Oral azithromycin 20 mg/kg (max 1 g) is WHO first-line for trachoma in children; topical: licensed from 1 year (oral — trachoma)

Clinical pearls

  • Trachoma — global significance: Chlamydia trachomatis (serovars A–C) is the leading cause of infectious blindness worldwide (1.9 million blind); WHO SAFE strategy (Surgery for trichiasis, Antibiotics for community treatment, Facial cleanliness, Environmental improvement); oral azithromycin 20 mg/kg single dose is first-line for both treatment and mass drug administration (MDA)
  • Topical 1.5% eye drops: DuraSite polymer vehicle extends drug contact time and allows effective tissue concentrations with simplified dosing (days 1–2 BD, days 3–7 OD); efficacy comparable to tobramycin QDS for bacterial conjunctivitis with better compliance due to fewer daily doses
  • Blepharitis/rosacea ocular: oral azithromycin 500 mg OD for 3 days (or 250 mg OD for 5 days) is effective for meibomian gland dysfunction associated with ocular rosacea — alternative to prolonged doxycycline courses; MHRA 2013 QTc warning — assess cardiac risk before prescribing
  • MHRA 2013 safety update: oral azithromycin associated with small increase in cardiovascular deaths and QTc prolongation — avoid in patients with known QTc prolongation, hypokalaemia, or concurrent QTc-prolonging drugs; obtain ECG if clinically indicated
  • Antibiotic resistance context: fluoroquinolone resistance in Streptococcus pneumoniae and Haemophilus influenzae is increasing; azithromycin (macrolide class) provides good coverage for atypical organisms and offers an alternative mechanism when fluoroquinolone resistance is suspected or documented

Contraindications

  • Macrolide hypersensitivity
  • Concurrent use with ergotamine or dihydroergotamine (oral azithromycin)

Side effects

  • Topical: transient stinging, blurred vision, eye irritation
  • Oral: nausea, diarrhoea, abdominal pain
  • QTc prolongation (oral — rare, dose-dependent)
  • MHRA 2013: oral azithromycin — cardiovascular events and QTc prolongation warning

Interactions

  • Oral azithromycin: antacids (reduce absorption), warfarin (INR increase), ciclosporin, statins — CYP3A4 substrate; topical: minimal interactions

Monitoring

  • Conjunctival and corneal clinical response at 48–72 hours
  • ECG if oral azithromycin in high-risk cardiac patients
  • Culture and sensitivity for recurrent or treatment-resistant cases

Reference: BNFc; BNF 90; MHRA Drug Safety Update 2013 (Azithromycin QTc); WHO SAFE Strategy for Trachoma; SPC AzaSite; RCOphth Bacterial Conjunctivitis Guidelines. Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.

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