Erythromycin is a commonly prescribed antibiotic for pink eye, known medically as conjunctivitis. Its use is strictly limited to infections caused by bacteria. Conjunctivitis is the inflammation of the conjunctiva, the membrane covering the white part of the eye and the inner eyelids. Since Erythromycin is an antibiotic, it is effective only against bacterial pathogens and offers no benefit for the more common viral or allergic forms of the condition.
Identifying the Different Types of Conjunctivitis
The redness, irritation, and discharge associated with pink eye stem from three main categories: bacterial, viral, and allergic. Bacterial conjunctivitis typically presents with a thick, sticky, pus-like discharge that is yellow or green, often causing the eyelids to stick together upon waking. While it can affect both eyes, it frequently starts in one eye before spreading to the other.
Viral conjunctivitis is the most frequent cause of pink eye and is highly contagious, often accompanying an upper respiratory infection like the common cold or flu. Unlike the bacterial form, viral pink eye typically produces a thin, watery, or clear discharge, and it does not respond to antibiotic treatment. This type of pink eye usually resolves on its own within one to two weeks.
Allergic conjunctivitis is not contagious and is triggered by environmental allergens such as pollen or pet dander. The hallmark symptom for this type is intense itching, usually affecting both eyes simultaneously, and it may be accompanied by other allergy symptoms like sneezing or a runny nose. Treatment for allergic pink eye involves antihistamines and avoiding the allergen, not antibiotics.
Erythromycin: Targeting Bacterial Infections
Erythromycin is a macrolide antibiotic designed to fight specific bacterial infections. The medication works by interfering with the bacteria’s ability to produce necessary proteins. It binds to the 50S subunit of the bacterial ribosome, blocking protein chain elongation.
This action is bacteriostatic, preventing bacteria from growing and reproducing rather than killing them outright. Halting the growth of the bacterial population allows the body’s immune system to clear the remaining infection. Erythromycin is effective against common bacterial strains that cause conjunctivitis, such as Staphylococcus and Streptococcus species.
Beyond treating established infections, Erythromycin ophthalmic ointment is routinely used as a preventive measure in newborns. This prophylaxis prevents Ophthalmia neonatorum, an infection contracted during birth from bacteria like Neisseria gonorrhoeae or Chlamydia trachomatis. A single application of a 0.5% ointment is typically administered shortly after delivery to prevent these potentially sight-threatening infections.
Proper Application and Treatment Duration
The effectiveness of Erythromycin relies on correct application technique and adherence to the prescribed schedule. Before handling the medication, thoroughly wash your hands to prevent contaminating the product or introducing new bacteria. Avoid touching the tip of the ointment tube or dropper to the eye, eyelid, or any other surface to keep the medicine sterile.
To apply the ointment, gently pull down the lower eyelid to create a small pocket. A thin strip of the ointment, typically about one centimeter in length, should be placed directly into this pocket. After application, the eye should be gently closed for one to two minutes to allow the medication to absorb and spread across the eye’s surface.
For active eye infections, the ointment is commonly applied four to six times a day. The standard duration of treatment is usually five to seven days. Completing the entire course of medication, even if symptoms improve quickly, is necessary to ensure the infection is fully eradicated and prevent antibiotic resistance.
Recognizing Adverse Reactions and When to Stop Treatment
Erythromycin ophthalmic preparations are generally well-tolerated, though mild and temporary side effects may occur at the application site. Patients commonly report temporary blurring of vision due to the ointment base, along with mild stinging, burning, or itching. If vision is temporarily blurry, avoid activities requiring clear sight, such as driving, until vision returns to normal.
More serious adverse reactions are rare, but signs of an allergic response require immediate medical attention. Severe symptoms include swelling of the face, lips, tongue, or throat, hives, or difficulty breathing. Discontinue use and contact a healthcare provider if eye symptoms worsen, if new pain or discharge develops, or if there is no noticeable improvement after 48 hours of treatment. A lack of improvement suggests the pink eye may be caused by a virus, an allergy, or a resistant bacterial strain.