What Is Polymyxin B Ointment?

Jacquelyn Gilchrist

Polymyxin B ointment is a medication used to treat bacterial infections of the eye. It is often combined with other medications, such as bacitracin zinc, terramycin, and neomycin. Polymyxin B ointment is an antibiotic that works by binding to the cell membranes of the bacteria. This damages the cells of the bacteria, resulting in cell death. A doctor may prescribe this drug to patients with blepharitis, keratitis, and conjunctivitis, also called pink eye, as well as some skin infections, such as infected ulcers.


Patients should always wash their hands thoroughly before and after applying polymyxin B ointment. To apply a dose, they should use a finger to gently pull the lower eyelid down, and then squeeze the prescribed amount of the ointment into the lower eyelid. They should then close their eyes for about two minutes. The applicator tip should never touch any surface, including the eyelid. Patients may be advised to avoid wearing contact lenses during an active eye infection.

Most people will not experience any side effects from the use of polymyxin B ointment. Rarely, some patients may suffer an allergic reaction, which requires prompt medical attention. Signs of a possible allergic reaction can include tightness in the chest, problems breathing, or hives. Itching, swelling of the face, or swelling of the eye, along with eye redness may also occur with an allergic reaction.

Other possible side effects may include dry or flaky skin, skin irritation, and minor itching. Some people may notice a slight burning or stinging sensation when a dose is applied. Those who experience persistent or severe side effects should consult the prescribing physician.

Certain precautions should be followed while using polymyxin B ointment to treat a bacterial eye infection. Patients should be aware that long-term use of the drug may lead to a secondary infection. The patient should always use the full course of the medicine, even if it appears that the infection is clearing up. Premature discontinuance of an antibiotic may lead to recurring infections or stronger infections in the future.

Before using polymyxin B ointment, patients should disclose their other medical conditions, medications, and supplements to prevent a possible adverse interaction. Women who are pregnant or breastfeeding should discuss possible risks with their doctors. Depending on any additional medications that polymyxin B may be combined with, the drug may pass into breast milk. This drug may be contraindicated for use by those with decreased kidney function, glaucoma, or certain allergies.

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