What eye drops are prescribed for a patient with conjunctivitis?

Eye Drops for Conjunctivitis

The choice of eye drops depends entirely on the etiology: topical fluoroquinolones (moxifloxacin 0.5% three times daily for 5-7 days) for bacterial conjunctivitis, topical antihistamines with mast cell stabilizers for allergic conjunctivitis, and supportive care with artificial tears for viral conjunctivitis—indiscriminate use of antibiotics or corticosteroids should be avoided. 1, 2

Bacterial Conjunctivitis

For uncomplicated bacterial conjunctivitis, topical moxifloxacin 0.5% is the preferred first-line treatment, administered three times daily for 7 days. 3 This fourth-generation fluoroquinolone provides superior gram-positive coverage including activity against Staphylococcus aureus, Streptococcus pneumoniae, and Haemophilus influenzae, with microbiological eradication rates of 84-94%. 2, 3

Alternative topical antibiotics include:

• Other fluoroquinolones: levofloxacin, gatifloxacin, ciprofloxacin, besifloxacin 2
• Older agents: gentamicin, tetracycline, or ofloxacin 0.3% (four times daily for 5-7 days) 2
• No single antibiotic has proven superiority over others, so choice can be based on dosing convenience, cost, and local resistance patterns 2

Critical caveat: Mild bacterial conjunctivitis is often self-limited, with 64% resolving spontaneously by days 6-10 without treatment. 2 Topical antibiotics provide earlier clinical and microbiological remission (68.2% cure rate vs 55.5% with placebo by days 4-9), allowing faster return to work or school. 4, 5

Special Bacterial Cases Requiring Systemic Antibiotics

Gonococcal conjunctivitis requires systemic therapy: ceftriaxone 250 mg IM single dose plus azithromycin 1 g oral single dose, with daily monitoring until resolution. 1, 2 Obtain conjunctival cultures and Gram staining before initiating treatment. 2

Chlamydial conjunctivitis requires systemic therapy: azithromycin 1 g oral single dose or doxycycline 100 mg twice daily for 7 days. 1, 2 Topical therapy alone is insufficient as more than 50% of patients have concurrent infection at other sites. 2

For neonatal bacterial conjunctivitis:

• Gonococcal: ceftriaxone 25-50 mg/kg IV or IM single dose 1
• Chlamydial: erythromycin base or ethylsuccinate 50 mg/kg/day oral divided in 4 doses for 14 days 1, 2
• Monitor infants receiving erythromycin for infantile hypertrophic pyloric stenosis 2

Viral Conjunctivitis

For adenoviral conjunctivitis (the most common viral cause), no proven effective antiviral treatment exists—management is supportive care only. 4, 2

Supportive measures include:

• Refrigerated preservative-free artificial tears four times daily to dilute viral particles and inflammatory mediators 1, 2
• Cold compresses for symptomatic relief 4, 2
• Topical antihistamines (second-generation) for itching and discomfort 1

Avoid topical antibiotics in viral conjunctivitis as they provide no benefit and contribute to antibiotic resistance and potential toxicity. 4, 1

Topical corticosteroids may be considered only in severe adenoviral cases with marked chemosis, eyelid swelling, epithelial sloughing, or membranous conjunctivitis, but require close monitoring for elevated intraocular pressure and cataract. 4, 2 Corticosteroids should be tapered to the minimum effective dose once inflammation is controlled, using agents with poor ocular penetration like fluorometholone or loteprednol to minimize side effects. 4

Herpes Simplex Virus (HSV) Conjunctivitis

For HSV conjunctivitis, topical options include ganciclovir 0.15% gel three to five times daily or trifluridine 1% solution five to eight times daily. 4, 1

Oral antivirals should be added: acyclovir 200-400 mg five times daily, valacyclovir 500 mg two to three times daily, or famciclovir 250 mg twice daily. 4, 1, 6

Critical warning: Topical corticosteroids are absolutely contraindicated in HSV epithelial infections as they potentiate viral replication and worsen the infection. 4, 1, 2 Topical trifluridine causes epithelial toxicity if used for more than 2 weeks, whereas ganciclovir is less toxic to the ocular surface. 4, 6

Allergic Conjunctivitis

Topical antihistamines with mast cell-stabilizing properties are the first-line treatment for allergic conjunctivitis. 4, 1, 2

Treatment algorithm:

• First-line: Second-generation topical antihistamine/mast cell stabilizers (e.g., olopatadine, ketotifen) 4, 1
• Adjunctive measures: Cold compresses, refrigerated preservative-free artificial tears, sunglasses as allergen barrier, avoiding eye rubbing 4, 1
• Second-line (if symptoms persist): Brief 1-2 week course of low side-effect profile topical corticosteroids (loteprednol or fluorometholone) with monitoring of intraocular pressure 4, 1, 7
• Severe refractory cases: Topical cyclosporine 0.05% to 1% or tacrolimus 4, 1

Avoid chronic use of topical vasoconstrictors as they cause rebound vasodilation. 4 Oral antihistamines may worsen dry eye syndrome and actually exacerbate allergic conjunctivitis by impairing the tear film's protective barrier. 4

Red Flags Requiring Immediate Ophthalmology Referral

Refer immediately if any of the following are present:

• Visual loss or decreased vision 1, 2
• Moderate to severe pain 1, 2
• Severe purulent discharge (suspect gonococcal infection) 1, 2
• Corneal involvement (infiltrate, ulcer, opacity) 1, 2
• Conjunctival scarring 1
• Lack of response to therapy after 3-4 days 1, 2
• History of HSV eye disease 1, 2
• Immunocompromised state 1, 2
• Neonatal conjunctivitis (requires systemic treatment coordinated with pediatrician) 1, 2

Common Pitfalls to Avoid

• Never use combination antibiotic-steroid drops (e.g., Tobradex) without definitively ruling out viral conjunctivitis, especially HSV and adenovirus. 2 Look for watery discharge, follicular reaction, and preauricular lymphadenopathy to identify viral causes. 2
• Do not prescribe oral antibiotics for routine bacterial conjunctivitis—they are reserved exclusively for gonococcal and chlamydial infections. 2
• Avoid punctal plugs in allergic conjunctivitis as they prevent flushing of allergens and inflammatory mediators from the ocular surface. 4
• Consider sexual abuse in preadolescent children with gonococcal or chlamydial conjunctivitis and document diagnosis by standard culture. 2
• Monitor patients on topical corticosteroids with periodic intraocular pressure measurements and pupillary dilation to evaluate for glaucoma and cataract. 4, 1

Infection Control

Strict hand hygiene with soap and water is essential to prevent transmission. 1, 2 Patients with viral conjunctivitis should avoid close contact for 7-14 days from symptom onset and discard multiple-dose eyedrop containers to avoid cross-contamination. 1