Neomycin, an aminoglyoside with antimicrobial spectrum similar to gentamicin, binds to the 30S subunits of the bacterial ribosome, inhibiting protein synthesis and thereby disrupting DNA synthesis. It is active against many gram-negative aerobes and against some strains of staphylococci.

Bacitracin, on the other hand, inhibits bacterial cell wall synthesis and is active against many gram-positive bacteria (e.g. staphylococci, streptococci, corynebacteria and Clostridia) and some gram-negative species (e.g. Neisseria and Haemophilus influenzae). They are often found in combinations in topical preparations as broad spectrum antibacterial agents.

Polymyxin B disrupts the bacterial cytoplasmic membrane of mostly gm-ve organisms allowing leakage of intracellular constituents by binding to membrane phospholipids.

This ophthalmic ointment or drop is indicated for the topical treatment of superficial infections of the external eye and its adnexa caused by susceptible bacteria. Such infections encompass conjunctivitis, keratitis and keratoconjunctivitis, blepharitis and blepharoconjunctivitis.

Eye Drop: 1-2 drops 3-4 times daily.

Eye ointment: Apply 1/2 inch ribbon of ointment to conjunctival sac of affected eye(s) q3-4hr for 7-10 days for acute infections

Hypersensitivity

Rash, itching, burning, anaphylactic reactions, swelling, conjunctival erythema.

Excessive use of the topical preparation may lead to substantial systemic absorption which may lead to nephrotoxicity (polymyxin B sulfate) and neurotoxicity (bacitracin). Prolonged use of the antibacterial preparation may cause overgrowth of non-susceptible organisms, including fungi. Pregnancy and lactation.

Use in Special Populations

Pediatric Use: Safety and effectiveness in pediatric patients have not been established.

Geriatric Use: No overall differences in safety or effectiveness have been observed between elderly and younger patients.

Pregnancy & Lactation

Pregnancy Category C. Animal reproduction studies have shown an adverse effect on the fetus and there are no adequate and well-controlled studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks

Lactation: Excretion in breast milk unknown; caution should be taken