From the Guidelines
For conjunctivitis, oral antibiotics are rarely needed and should be reserved for severe bacterial infections with systemic symptoms or when there's significant periorbital cellulitis, as indicated in the 2024 conjunctivitis preferred practice pattern 1. Most bacterial conjunctivitis cases should be treated with topical antibiotic ointments or drops. Common topical options include:
- erythromycin ointment (0.5%, apply 1/2 inch to the conjunctival sac 2-4 times daily for 7-10 days)
- polymyxin B-trimethoprim drops (1 drop every 3 hours while awake for 7-10 days)
- fluoroquinolone drops like moxifloxacin (1 drop 3 times daily for 7 days) Ointments provide longer contact time but may blur vision temporarily, making drops preferable for daytime use. Viral conjunctivitis, which is more common, doesn't respond to antibiotics and requires only supportive care. Allergic conjunctivitis should be treated with antihistamines or mast cell stabilizers. When prescribing, consider that bacterial conjunctivitis is often self-limiting within 7-10 days, so antibiotics mainly help reduce contagion and shorten symptom duration, as noted in the 2024 study on conjunctivitis preferred practice pattern 1. Patients should be advised to avoid sharing towels or pillows and to practice good hand hygiene to prevent spread. The choice of antibiotic is usually empiric, and because a 5- to 7-day course of a broad-spectrum topical antibiotic is usually effective, the most convenient or least expensive option can be selected, as stated in the 2024 conjunctivitis preferred practice pattern 1. In cases where access to antibiotics is limited, povidone-iodine 1.25% ophthalmic solution may be considered as an alternative, as suggested in the 2024 study on conjunctivitis preferred practice pattern 1. For severe bacterial infections, such as those caused by gonococcus or chlamydia, oral antibiotics like azithromycin or doxycycline may be necessary, as indicated in the 2024 conjunctivitis preferred practice pattern 1. In neonates, ocular prophylaxis with erythromycin 0.5% ophthalmic ointment is recommended, as stated in the 2024 conjunctivitis preferred practice pattern 1. The Working Group on essential medicines and aware recommendations also suggests that topical antibiotics should be considered for mild cases of conjunctivitis, as they reduce the duration of symptoms, as noted in the 2024 study on who's essential medicines and aware 1.
From the FDA Drug Label
DOSAGE AND ADMINISTRATION: The ointment should be applied directly into the conjunctival sac 1 to 3 times daily. The FDA drug label does not answer the question.
From the Research
Decision Factors for Oral vs Ointment Antibiotics
When deciding between oral and ointment antibiotics for conjunctivitis, several factors should be considered:
- The cause of the conjunctivitis: bacterial, viral, or allergic 2
- The severity of the infection: mild, moderate, or severe 3
- The presence of underlying conditions: immunocompromised patients, newborns, or contact lens wearers 4, 5
- The risk of complications: corneal scarring, systemic infections, or perinatal transmission 3, 5
Treatment Guidelines
- For uncomplicated bacterial conjunctivitis, topical antibiotics such as azithromycin or fluoroquinolones are usually prescribed 4, 3
- For gonococcal and chlamydial conjunctivitis, systemic antibiotics are necessary due to the potential for severe complications 3, 2, 5
- For allergic conjunctivitis, topical antihistamines and mast cell stabilizers are recommended 2
- For viral conjunctivitis, treatment is supportive, and antibiotics are not necessary 2
Antibiotic Resistance and Treatment Duration
- The development of antibiotic resistance is a concern, and treatment should be tailored based on antibiotic susceptibility profiles 4, 3
- Topical antibiotics have been shown to decrease the duration of bacterial conjunctivitis and allow earlier return to school or work 2, 6
- The treatment duration and frequency of antibiotic administration should be determined based on the severity of the infection and the patient's response to treatment 6