Medically Reviewed on 6/2/2023

Generic Name: neomycin/polymyxin B/gramicidin ophthalmic

Brand Names: Gramicidin, Neosporin Ophthalmic Solution, Neocin-PG

Drug Class: Antibiotics, Ophthalmic Combos

What is neomycin/polymyxin B/gramicidin ophthalmic, and what is it used for?

Neomycin/polymyxin B/gramicidin ophthalmic is an antibiotic eye drop topically applied on the eye to prevent and treat superficial eye infections and inflammations. Neomycin/polymyxin B/gramicidin ophthalmic is a combination of three antibiotics that together provide activity against a wider spectrum of bacterial strains than any of them as a single agent. 

Each of the three antibiotics in the combination works in different ways to stop the growth (bacteriostatic) or kill the bacteria (bactericidal):

  • Neomycin: Neomycin is a broad-spectrum aminoglycoside antibiotic that is bactericidal for both gram-positive and gram-negative bacteria. Neomycin prevents the synthesis of proteins that bacteria require to grow and survive. Neomycin binds to 30S subunits in the bacterial ribosomes (cellular particles that synthesize proteins) and prevents the formation of peptide chains, which results in bacterial cell wall damage and cell death.
  • Polymyxin B: Polymyxin B is a bactericidal drug that binds to fatty molecules on the outer cell membranes of gram-negative bacteria, increases the permeability of the cell membrane and causes leakage of cell contents leading to bacterial death.
  • Gramicidin: Gramicidin binds to and gets inserted into bacterial membranes and makes it more permeable, causing leakage of cell contents. In addition, gramicidin also disrupts bacterial metabolic functions, protein synthesis and DNA functions, killing the bacteria. Gramicidin is particularly effective against gram-positive bacteria.

Neomycin/polymyxin B/gramicidin combination has activity against both gram-positive and gram-negative bacteria. The two classes of bacteria are structurally different and identified by the Gram stain lab test. Gram-negative bacteria have an additional membrane outside the cell wall that gram-positive bacteria lack. Organisms susceptible to the combo antibiotic include:

Neomycin/polymyxin B/gramicidin ophthalmic is used for the following types of eye infections:


  • Do not use in patients with hypersensitivity to neomycin, aminoglycosides or any component of neomycin/polymyxin B/gramicidin ophthalmic solution.
  • Neomycin/polymyxin B/gramicidin can cause allergic cross-reactions which could prevent the use of any or all of certain antibiotics for treatment of future infections, including kanamycin, paromomycin, streptomycin, and possibly gentamicin.
  • Never inject neomycin/polymyxin B/gramicidin ophthalmic solution into the eye.
  • Monitor patients for neomycin sensitization symptoms that may include itching, redness, edema and failure to heal.
  • Prolonged use of neomycin/polymyxin B/gramicidin ophthalmic can:
    • Cause diminished visual acuity, posterior subcapsular cataract formation and glaucoma, a condition with high intraocular pressure that gradually damages the optic nerve.
    • Result in overgrowth of non-susceptible organisms including fungi. Monitor patients of superinfections and treat appropriately.
    • Secondary eye infections. Monitor and treat appropriately.
    • Lead to development of bacterial resistance. Advise patients to discontinue use and report if purulent discharge, pain and inflammation are aggravated.


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What are the side effects of neomycin/polymyxin B/gramicidin ophthalmic?

Common side effects of neomycin/polymyxin B/gramicidin ophthalmic include:

Call your doctor immediately if you experience any of the following symptoms or serious side effects while using this drug:

This is not a complete list of all side effects or adverse reactions that may occur from the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may also report side effects or health problems to the FDA at 1-800-FDA-1088.

What are the dosages of neomycin/polymyxin B/gramicidin ophthalmic?

Ophthalmic solution

  • (1.75 mg/10,000/0.025 mg)/1 mL (10 mL)

Adult and Pediatric:

Treatment and Prevention of Ocular Infection and/or Inflammation

  • 1-2 drops every 4-6 hours for 7-10 days; if severe 2 drops every 1 hour if necessary


There is no information on overdose of neomycin/polymyxin B/gramicidin ophthalmic solution. Oral ingestion and overdose may be harmful. Prolonged use of antibiotics can cause overgrowth of non-susceptible organisms and development of bacterial resistance. Treatment is discontinuation of neomycin/polymyxin B/gramicidin ophthalmic and treatment with appropriate antimicrobial medications.

What drugs interact with neomycin/polymyxin B/gramicidin ophthalmic?

Inform your doctor of all medications you are currently taking, who can advise you on any possible drug interactions. Never begin taking, suddenly discontinue, or change the dosage of any medication without your doctor’s recommendation.

  • Severe interactions of neomycin/polymyxin B/gramicidin ophthalmic include:
    • aminoglycosides
    • bacitracin
    • BCG intravesical
    • cholera vaccine
    • fecal microbiota (live) oral
    • fecal microbiota (live) rectal
    • mecamylamine
    • methoxyflurane
    • netilmicin ophthalmic
  • Serious interaction of neomycin/polymyxin B/gramicidin ophthalmic include:
    • Bacillus clausii
    • colistimethate
    • kanamycin
    • neuromuscular blocking agents
    • sodium picosulfate
    • typhoid vaccine
  • Moderate interactions of neomycin/polymyxin B/gramicidin ophthalmic include:
    • BCG vaccine
    • capreomycin
    • cefazedone
    • cephaloridine
    • immune checkpoint inhibitors (anti-PD-1, -PD-L1, and -CTLA4 therapies)
    • lactobacillus and estriol
  • Neomycin/polymyxin B/gramicidin ophthalmic has no known mild interactions with other drugs.

The drug interactions listed above are not all of the possible interactions or adverse effects. For more information on drug interactions, visit the RxList Drug Interaction Checker.

It is important to always tell your doctor, pharmacist, or health care provider of all prescription and over-the-counter medications you use, as well as the dosage for each, and keep a list of the information. Check with your doctor or health care provider if you have any questions about the medication.

Pregnancy and breastfeeding

  • There are no animal reproductive studies on the safety of neomycin/polymyxin B/gramicidin ophthalmic use during pregnancy, and it is not known if it can cause fetal harm or affect reproductive capacity. The combination antibiotic should be used in pregnant women only if it is clearly needed.
  • It is not known if neomycin/polymyxin B/gramicidin ophthalmic is present in breastmilk. Use with caution in nursing mothers, because many drugs are excreted in breastmilk.

What else should I know about neomycin/polymyxin B/gramicidin ophthalmic?

  • Use neomycin/polymyxin B/gramicidin ophthalmic exactly as directed.
  • Neomycin/polymyxin B/gramicidin ophthalmic solution is for topical ophthalmic use only.
  • Do not share your eye drop dispenser with others, it can spread infection.
  • Do not allow the tip of the ophthalmic solution container to come into contact with any surface to avoid contamination. Use of contaminated eyedrops can result in infections, serious damage to the eye and even loss of vision.
  • Exercise care to avoid contact of container tip to the eye to prevent injury to the eye.
  • Complete the prescribed antibiotic course. Do not skip doses or discontinue therapy if you feel better, it can decrease effectiveness of treatment and can also lead to development of drug-resistant bacteria.
  • Stop use of neomycin/polymyxin B/gramicidin ophthalmic and consult your physician if:
    • You develop hypersensitivity reactions
    • You experience symptoms such as eye itching, redness and edema and the inflammation fails to heal
    • Your condition persists or worsens
  • Store neomycin/polymyxin B/gramicidin ophthalmic safely out of reach of children
  • In case of accidental oral ingestion and overdose, seek immediate medical help or contact Poison Control.

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Neomycin/polymyxin B/gramicidin ophthalmic is an antibiotic eye drop topically applied on the eye to prevent and treat superficial eye infections and inflammations. Neomycin/polymyxin B/gramicidin ophthalmic is used to treat eye infections, including conjunctivitis, infection of the cornea (keratitis), keratoconjunctivitis, eyelid infection (blepharitis), and blepharoconjunctivitis. Common side effects include irritation, swelling, itching, skin redness, hives (urticaria), vesicular and maculopapular dermatitis, and severe allergic reaction.

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You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.

Medically Reviewed on 6/2/2023