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Overview: Polymyxin B/trimethoprim ophthalmic is used to treat bacterial eye infections like conjunctivitis and blepharoconjunctivitis. It works by killing bacteria and weakening their cell walls. Common side effects include redness, itching, burning, or stinging in the eye. Call your health care provider right away if you have a rash, itching or swelling, trouble breathing, or if your eye infection does not improve or gets worst.

Uses

What is polymyxin B/trimethoprim ophthalmic used for?

Polymyxin B/trimethoprim ophthalmic (eye) is commonly used for certain eye infections caused by bacteria, including the following. 

  • Conjunctivitis (pink eye), which is a condition in which part of your eye is inflamed, sometimes from bacteria
  • Blepharoconjunctivitis, which is a condition in which part of your eye and eyelid is inflamed, sometimes from bacteria

Polymyxin B/trimethoprim ophthalmic may not be the right medicine for some of the infections listed above, depending on which germs are causing the infection. Bacteria in some locations may have become resistant to polymyxin B/trimethoprim ophthalmic, which will make it not work as well.

Polymyxin B/trimethoprim ophthalmic may also be used for other conditions as determined by your health care provider.

How does polymyxin B/trimethoprim ophthalmic work (mechanism of action)?

Polymyxin B/trimethoprim ophthalmic kills certain types of bacteria by blocking their ability to create proteins or other substances that they need to grow and reproduce and by weakening their cell membrane.

How is polymyxin B/trimethoprim ophthalmic supplied (dosage forms)?

Brands and other names

  • Polytrim

Dosage forms and strengths

  • 10,000 units/1 mg per mL eye drops

How should I store polymyxin B/trimethoprim ophthalmic?

Polymyxin B/trimethoprim ophthalmic should be stored at room temperature, between 59 F and 77 F (15 C and 25 C). Store in a cool, dry place. Protect from light. Keep the medicine in its box until you are ready to use it.

Side Effects

What are the most common side effects of polymyxin B/trimethoprim ophthalmic?

The most common side effects of polymyxin B/trimethoprim ophthalmic are listed below. Tell your health care provider if you have any of these side effects that bother you.

  • Eye redness or itching
  • Eye burning or stinging

There may be other side effects of polymyxin B/trimethoprim ophthalmic that are not listed here. Contact your health care provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088 (800-332-1088). In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of polymyxin B/trimethoprim ophthalmic?

While less common, the most serious side effects of polymyxin B/trimethoprim ophthalmic are described below, along with what to do if they happen.

Severe Allergic Reactions. Polymyxin B/trimethoprim ophthalmic may cause allergic reactions, which can be serious. Stop using polymyxin B/trimethoprim ophthalmic and get help right away if you have any of the following symptoms of a serious allergic reaction.

  • Breathing problems or wheezing
  • Racing heart
  • Fever or general ill feeling
  • Swollen lymph nodes
  • Swelling of the face, lips, mouth, tongue, or throat
  • Trouble swallowing or throat tightness
  • Itching or skin rash
  • Bumps on the skin called hives that can be red, pink, white, or brown depending on your skin tone
  • Nausea or vomiting
  • Dizziness, feeling lightheaded, or fainting
  • Stomach cramps
  • Joint pain

Another Infection With Prolonged Use. Using polymyxin B/trimethoprim ophthalmic for a prolonged period of time may lead to an infection with other types of germs, such as fungi. Call your health care provider if your eye infection does not improve or gets worse.

Warnings & Precautions

Who should not use polymyxin B/trimethoprim ophthalmic?

Allergies to Ingredients. People who are allergic to any of the following should not use polymyxin B/trimethoprim ophthalmic.

  • Polymyxin B/trimethoprim 
  • Polytrim
  • Any of the ingredients in the specific product dispensed

Your pharmacist can tell you all of the ingredients in the specific polymyxin B/trimethoprim ophthalmic products they stock.

What should I know about polymyxin B/trimethoprim ophthalmic before using it?

Do not use polymyxin B/trimethoprim ophthalmic unless it has been prescribed to you by a health care provider. 

Use polymyxin B/trimethoprim ophthalmic as prescribed. Using it in a way other than it was prescribed may increase the chance that the bacteria will become resistant to polymyxin B/trimethoprim ophthalmic. This may cause polymyxin B/trimethoprim ophthalmic to not work as well in the future. 

Only use polymyxin B/trimethoprim ophthalmic for an infection if your health care provider has prescribed it for this reason. If symptoms of an infection return after using polymyxin B/trimethoprim ophthalmic, contact your health care provider.

Do not share polymyxin B/trimethoprim ophthalmic with other people, even if they have the same condition as you. It may harm them.

Keep polymyxin B/trimethoprim ophthalmic out of the reach of children.

Polymyxin B/trimethoprim ophthalmic should only be applied to the surface of the eye. Do not touch the tip of the medicine to your eye or any other surface including your finger. Do not inject polymyxin B/trimethoprim ophthalmic into the eye.

Do not wear contact lenses during your treatment with polymyxin B/trimethoprim ophthalmic.

What should I tell my health care provider before using polymyxin B/trimethoprim ophthalmic?

Tell your health care provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them know if polymyxin B/trimethoprim ophthalmic is right for you.

In particular, make sure that you discuss any of the following.

Pregnancy. It is not known if or how polymyxin B/trimethoprim ophthalmic could affect pregnancy or harm a fetus. Tell your health care provider if you are or plan to become pregnant. Your health care provider will let you know if you should use polymyxin B/trimethoprim ophthalmic while you are pregnant or trying to get pregnant.

Breastfeeding. It is not known if polymyxin B/trimethoprim ophthalmic passes into breast milk. Tell your health care provider if you are breastfeeding or plan to breastfeed. Your health care provider will let you know if you should use polymyxin B/trimethoprim ophthalmic while breastfeeding.

Interactions

Does polymyxin B/trimethoprim ophthalmic interact with foods or drinks?

There are no known interactions between polymyxin B/trimethoprim ophthalmic and foods or drinks.

It is unknown if drinking alcohol will affect polymyxin B/trimethoprim ophthalmic, but heavy drinking can slow your immune response and make it harder for your body to fight infection.

Does polymyxin B/trimethoprim ophthalmic interact with other medicines (drug interactions)?

There are no known interactions between polymyxin B/trimethoprim ophthalmic and other medicines. Always tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

Does interact with other drugs you are taking?

Enter your medication into the WebMD interaction checker

Overdose/Missed Dose

What should I do if I accidentally use too much polymyxin B/trimethoprim ophthalmic?

If you or someone else has used too much polymyxin B/trimethoprim ophthalmic, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

What should I do if I miss a dose of polymyxin B/trimethoprim ophthalmic?

If you miss a dose, use it as soon as you remember. If it is almost time for your next dose, skip the missed dose and only use the next dose. Do not use double or extra doses. 

It is important to complete your prescribed course of polymyxin B/trimethoprim ophthalmic, even if your symptoms get better or go away. This will reduce the risk that future infections are resistant to polymyxin B/trimethoprim ophthalmic or other similar medicines.