How Do Ophthalmic Antibiotics/Corticosteroids Work?

Ophthalmic antibiotic/corticosteroid combinations are effective against inflammation as well as bacterial infection in the eyes. Antibiotics kill bacteria and prevent their growth, while corticosteroids are anti-inflammatory and work by reducing swelling and irritation in the eyes.

Inflammation results when the body’s immune system releases pro-inflammatory proteins (cytokines) that flow out through the tiny blood vessels (capillaries) to fight the bacteria at the infection site. Corticosteroids decrease capillary permeability, prevent the cytokines from flowing out of the capillaries, and relieve the symptoms of inflammation.

Ophthalmic antibiotics work by killing the bacteria that entered the eye and caused the infection and inhibit bacterial growth in the following ways:

• Create fissures in the bacterial cell membrane, causing cell contents to leak out, and enable absorption of the antibiotic into the bacterial cell
• Prevent the bacteria from using amino acids and enzymes to synthesize proteins and folic acid required for their survival
• Prevent the growth of bacterial cell walls, the layer over the bacterial cell membrane, which protects them when they grow and helps maintain their shape

Ophthalmic antibiotic/corticosteroid drugs are topical applications administered in the eyes, in the form of ointments or suspensions.

Ophthalmic antibiotics/corticosteroids are used to treat conditions that include:

• Conjunctivitis (inflammation of the conjunctiva which includes the whites of the eye and the inner surface of eyelids)
• Steroid-responsive inflammation in the eyes with an existing bacterial infection or a risk for developing bacterial infection

Side effects of ophthalmic antibiotics/corticosteroids may include:

• Blurred vision
• Cataract formation
• Increase in intraocular pressure (pressure inside the eyeball)
• Glaucoma (high intraocular pressure that can lead to vision loss)
• Eye irritation, pain and stinging
• Itching and swelling of eyelids
• Eye tearing and discharge
• Eye edema
• Conjunctival redness and/or hemorrhage
• Vitreous detachment (detachment of vitreous, a gel-like substance inside the eye, from the retina), a condition that causes floaters in the eye
• Punctate keratitis (inflammation in the cornea)
• Ulcerative keratitis (inflammation with ulceration in the cornea)
• Headache
• Dizziness
• Delayed wound healing
• Secondary infections
• Fungal infections in the cornea
• Superinfections such as herpes
• Damage to the optic nerve (rare) and impairment to vision
• Dysgeusia (taste disorder)
• Hypersensitivity reaction such as:
  • Rash
  • Hives
  • Itching
  • Swelling
  • Erythema multiforme (a skin condition with red patchy lesions)
  • Stevens-Johnson syndrome (a rare medical emergency with flu-like symptoms and a painful rash)
  • Anaphylaxis (severe allergic reaction)

The information contained herein is not intended to cover all possible side effects, precautions, warnings, drug interactions, allergic reactions, or adverse effects. Check with your doctor or pharmacist to make sure these drugs do not cause any harm when you take them along with other medicines. Never stop taking your medication and never change your dose or frequency without consulting your doctor.

Generic and brand names of ophthalmic antibiotic/corticosteroid drugs include:

• Dexamethasone/neomycin sulfate/polymyxin B sulfate (Maxitrol, Dexasporin)
• Dexamethasone/tobramycin (TobraDex, TobraDex ST)
• Prednisolone acetate/gentamicin sulfate (Pred G)
• Prednisolone acetate/sulfacetamide sodium (Blephamide, Blephamide S.O.P.)
• Tobramycin/loteprednol etabonate (Zylet)