What oral antibiotic is recommended for treating bacterial conjunctivitis?

Oral Antibiotics for Bacterial Conjunctivitis

For bacterial conjunctivitis requiring oral antibiotic therapy, azithromycin 1g as a single oral dose is the recommended first-line treatment for adults, while children should receive age-appropriate therapy based on weight and suspected pathogen. 1

Indications for Oral Antibiotics in Conjunctivitis

Most cases of bacterial conjunctivitis are treated with topical antibiotics or resolve spontaneously. Oral antibiotics are primarily indicated for:

• Suspected or confirmed gonococcal or chlamydial conjunctivitis
• Severe cases unresponsive to topical therapy
• Cases with systemic involvement
• Specific pathogens requiring systemic treatment

Recommended Oral Antibiotic Regimens by Age and Pathogen

Adults

• Chlamydial conjunctivitis:

  • Azithromycin 1g orally as a single dose (preferred) 1
  • OR Doxycycline 100mg orally twice daily for 7 days 1

• Gonococcal conjunctivitis:

  • Ceftriaxone (IM injection) plus oral therapy for potential chlamydial co-infection 1

Children

• Children ≥8 years:

  • Azithromycin 1g orally as a single dose 1
  • OR Doxycycline 100mg orally twice daily for 7 days (if ≥45kg) 1

• Children <8 years but ≥45kg:

  • Azithromycin 1g orally as a single dose 1

• Children <45kg:

  • Erythromycin base or ethylsuccinate 50mg/kg/day orally divided into four doses for 14 days 1

Neonates

• Chlamydial conjunctivitis:

  • Erythromycin base or ethylsuccinate 50mg/kg/day orally divided into four doses for 14 days 1

• Gonococcal conjunctivitis:

  • Ceftriaxone 25-50mg/kg IV or IM as a single dose (not to exceed 125mg) 1, 2

Special Considerations

Pregnancy

• Pregnant women should not receive doxycycline, quinolones, or tetracyclines
• Recommended alternatives for pregnant women:
  • Erythromycin
  • Amoxicillin 1

Monitoring and Follow-up

• Patients treated for gonococcal or chlamydial infections should be retested approximately 3 months after treatment 1
• Infants treated with erythromycin should be monitored for signs of infantile hypertrophic pyloric stenosis, particularly those under 6 weeks of age 1

Important Cautions

• Sexual abuse must be considered in preadolescent children with gonococcal or chlamydial infections 1
• For suspected gonococcal infections, consider lavage of infected eyes with saline solution once 1
• Patients with chlamydial or gonococcal conjunctivitis should be evaluated for other sexually transmitted infections 1

Treatment Algorithm

1. Identify suspected pathogen based on clinical presentation and patient demographics
2. For typical bacterial conjunctivitis with no systemic involvement, use topical antibiotics
3. For suspected chlamydial infection:
   • Adults: Azithromycin 1g orally (single dose)
   • Children ≥8 years: Azithromycin 1g orally (single dose)
   • Children <8 years: Erythromycin for 14 days
4. For suspected gonococcal infection:
   • Parenteral ceftriaxone plus oral therapy for potential chlamydial co-infection
   • Consider saline lavage

While topical antibiotics are the mainstay of treatment for most cases of bacterial conjunctivitis 2, oral antibiotics are essential for specific pathogens and presentations, particularly those caused by sexually transmitted organisms.