What are the appropriate antibiotics (abx) for the treatment of conjunctivitis?

From the Guidelines

For bacterial conjunctivitis, a 5- to 7-day course of a broad-spectrum topical antibiotic is usually effective, and the most convenient or least expensive option can be selected, as there is no clinical evidence suggesting the superiority of any particular antibiotic. When considering treatment for conjunctivitis, it's crucial to distinguish between viral, allergic, and bacterial causes, as the majority of cases are viral or allergic and will resolve without antibiotic treatment 1. For bacterial conjunctivitis, topical antibiotics may be prescribed, with common first-line options including erythromycin 0.5% ointment or fluoroquinolone drops such as moxifloxacin 0.5% or ciprofloxacin 0.3% 1.

Key Considerations

• Bacterial conjunctivitis typically presents with purulent discharge and may affect one eye initially before spreading, while viral conjunctivitis often presents with watery discharge and may be associated with upper respiratory symptoms.
• Antibiotics should be used only when bacterial etiology is suspected to avoid unnecessary treatment and antibiotic resistance.
• Patients should be advised to practice good hygiene, avoid touching or rubbing the eyes, use separate towels, and wash hands frequently to prevent spread of infection.
• In cases of moderate to severe bacterial conjunctivitis, conjunctival cultures and slides for Gram staining should be obtained to guide the choice of antibiotic, especially if gonococcal infection is a possibility 1.

Treatment Options

• Erythromycin 0.5% ointment applied 3-4 times daily.
• Fluoroquinolone drops such as moxifloxacin 0.5% or ciprofloxacin 0.3% used 1-2 drops every 2-4 hours while awake for the first 1-2 days, then 4 times daily for 5-7 days total.
• Polymyxin B-trimethoprim drops used 1-2 drops every 3 hours while awake for 7-10 days.
• Povidone-iodine 1.25% ophthalmic solution may be considered as an alternative to topical antibiotic therapy, especially in low- to middle-income countries where access to antibiotics is limited 1.

From the FDA Drug Label

Moxifloxacin ophthalmic solution, 0.5% is indicated for the treatment of bacterial conjunctivitis caused by susceptible strains of the following organisms: Corynebacterium species* Micrococcus luteus* Staphylococcus aureus Staphylococcus epidermidis Staphylococcus haemolyticus Staphylococcus hominis Staphylococcus warneri* Streptococcus pneumoniae Streptococcus viridans group Acinetobacter lwoffii* Haemophilus influenza Haemophilus parainfluenzae* Chlamydia trachomatis Instill one drop in the affected eye 3 times a day for 7 days.

Moxifloxacin ophthalmic solution is used to treat bacterial conjunctivitis. The recommended dosage is one drop in the affected eye, three times a day, for 7 days 2.

• Key organisms that moxifloxacin is effective against include:
  • Staphylococcus species
  • Streptococcus species
  • Haemophilus species
  • Chlamydia trachomatis It is essential to note that hypersensitivity reactions can occur with moxifloxacin use, and patients should be advised not to wear contact lenses if they have signs or symptoms of bacterial conjunctivitis 2.

From the Research

Antibiotics for Conjunctivitis

• The use of antibiotics such as moxifloxacin 0.5% ophthalmic solution 3 and azithromycin 1.5% eye drops 4, 5, 6 has been shown to be effective in the treatment of bacterial conjunctivitis.
• Moxifloxacin 0.5% ophthalmic solution has been found to have good activity against various Gram-positive and -negative ocular isolates in vitro, and achieved good penetration into ocular tissues in healthy volunteers and patients undergoing ocular surgery 3.
• Azithromycin 1.5% eye drops have been shown to be non-inferior to tobramycin 0.3% eye drops in the treatment of purulent bacterial conjunctivitis, with a more convenient twice-a-day dosing regimen 4, 6.
• Azithromycin 1% ophthalmic solution has also been found to be effective in the treatment of bacterial conjunctivitis, with a statistically significant difference in clinical resolution and bacterial eradication rates compared to vehicle 5.

Treatment Options

• Moxifloxacin 0.5% ophthalmic solution is available for use in the treatment of bacterial conjunctivitis, with a dosing strategy of three times daily for 5 days 3, 7.
• Azithromycin 1.5% eye drops are available for use in the treatment of purulent bacterial conjunctivitis, with a dosing regimen of twice daily for 3 days 4, 6.
• Tobramycin 0.3% eye drops are also available for use in the treatment of purulent bacterial conjunctivitis, with a dosing regimen of every 2 hours for 2 days, then four times daily for 5 days 4, 6.

Efficacy and Safety

• Moxifloxacin 0.5% ophthalmic solution has been found to be well tolerated in patients with bacterial conjunctivitis, with ocular adverse events such as eye pain and eye irritation being the most commonly reported treatment-related adverse events 3.
• Azithromycin 1.5% eye drops have been found to be safe and well tolerated in patients with purulent bacterial conjunctivitis, with a good patient and investigator's acceptability 4, 6.
• Azithromycin 1% ophthalmic solution has also been found to be well tolerated in patients with bacterial conjunctivitis, with adverse event rates similar to those of vehicle 5.