polymyxin b/trimethoprim
Polytrim (polymyxin B / trimethoprim) is a combination antibiotic eye drop. It's used to treat mild-to-moderate bacterial eye infections, such as pink eye, in adults and children ages 2 months and older. The typical dose is 1 drop applied directly in the eye(s) every 3 hours for 7 to 10 days. Some of the more common side effects of this eye drop include symptoms of eye irritation, such as redness, stinging, and itching. Polytrim (polymyxin B / trimethoprim) is available as a lower-cost generic.
What is Polytrim (polymyxin B / trimethoprim)?
What is Polytrim (polymyxin B / trimethoprim) used for?
Mild-to-moderate infections on the eye and eyelid
How Polytrim (polymyxin B / trimethoprim) works
Polytrim (polymyxin B / trimethoprim) is a combination of two antibiotics that work together to kill bacteria:
Polymyxin B: is a polypeptide antibiotic that breaks the outer protective covering that bacteria need to grow and survive.
Trimethoprim is an antifolate. It works by stopping bacteria from being able to make a substance (folic acid) that's needed for them to grow and survive.
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What are the side effects of Polytrim (polymyxin B / trimethoprim)?
Common Side Effects
- Eye irritation (e.g., redness, burning, stinging, itching)
Other Side Effects
- Swollen eyelid(s)
- Red eyes
- Tearing
Serious Side Effects
- Severe allergic reaction: hives; trouble breathing; swelling in the face, tongue, or throat
Source: DailyMed
The following side effects have also been reported
Side effects that you should report to your care team as soon as possible:
- Allergic reactions—skin rash, itching, hives, swelling of the face, lips, tongue, or throat
- New or worsening eye pain, redness, irritation, or discharge
Side effects that usually do not require medical attention (report to your care team if they continue or are bothersome):
- Eye irritation or itching
- Increased tears after use
Pros and cons of Polytrim (polymyxin B / trimethoprim)
Pros
Can treat a variety of eye infections in adults and children
Available as a lower-cost generic
Applied directly on the eyes, so it has less side effects than oral antibiotics
Cons
Has to be used every 3 hours for at least a week
Can cause temporary eye irritation after applying
Can make your eyes more sensitive to light
Pharmacist tips for Polytrim (polymyxin B / trimethoprim)
Make sure to take Polytrim (polymyxin B / trimethoprim) exactly as prescribed. Use the medication even if you start to feel better. Stopping Polytrim (polymyxin B / trimethoprim) too soon can cause your infection to come back and be harder to treat.
Let your optometrist know if you wear contacts. They might recommend you wear glasses while you're using Polytrim (polymyxin B / trimethoprim). It's generally recommended to not wear contacts while you have an eye infection because they can affect how quickly you recover from the infection or become contaminated with the bacteria that's in your eye.
Wash your hands before and after using Polytrim (polymyxin B / trimethoprim). To avoid spreading germs into the medication or spreading the infection to other people, don't touch the dropper tip to any surface, including your eye, eyelids, or ear.
How to use Polytrim (polymyxin B / trimethoprim): To use Polytrim (polymyxin B / trimethoprim), tilt your head backward and look up. Then, gently pull your lower eyelid down to form a small pocket and squeeze one drop of medication into this pocket. Don't blink or wipe your eyes. Close your eyes while pressing a finger against the inside corner of your eye for about 1 minute to help keep the medication in your eye.
Make sure to keep the Polytrim (polymyxin B / trimethoprim) bottle capped and closed tightly when you're not using it. Don't share the medication with anyone to prevent the infection from spreading to other people.
If you're using Polytrim (polymyxin B / trimethoprim) at the same time as other eye drop medications, wait at least 5 minutes between each medication to give your eyes time to absorb each medication.
Keep the Polytrim (polymyxin B / trimethoprim) bottle at room temperature. Don't put it in the fridge or freezer.
Frequently asked questions about Polytrim (polymyxin B / trimethoprim)
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What are the risks and warnings for Polytrim (polymyxin B / trimethoprim)?
Polytrim (polymyxin B / trimethoprim) can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
For use in the eye only
Polytrim (polymyxin B / trimethoprim) are drops that should only be placed on the surface of the eye. Don't apply Polytrim (polymyxin B / trimethoprim) to any other place on your body.
New infection
Risk factors: Using Polytrim (polymyxin B / trimethoprim) for too long
It's possible to get a new infection from fungi or bacteria that are resistant to Polytrim (polymyxin B / trimethoprim) after using this medication for a while. Don't use this medication longer than prescribed. Let your eye provider know if you notice symptoms of a new infection or if the original symptoms do not get better after using Polytrim (polymyxin B / trimethoprim).
Damage to contact lenses (when used in the eye)
Polytrim (polymyxin B / trimethoprim) contains a preservative called benzalkonium chloride. This preservative can get absorbed into soft contact lenses and damage them. If your eye provider said you can wear contact lenses during treatment, take them out before you use the eye drops. Wait at least 15 minutes after using the medication to put them back into your eye(s).
Polytrim (polymyxin B / trimethoprim) dosage forms
Typical dosing for Polytrim (polymyxin B / trimethoprim)
The typical dose is 1 drop in the affected eye(s) every 3 hours for 7 to 10 days. Don't use more than 6 doses per day.
How much does Polytrim (polymyxin B / trimethoprim) cost?
Polytrim (polymyxin B / trimethoprim) contraindications
Severe allergy to polymyxin B or trimethoprim
What are alternatives to Polytrim (polymyxin B / trimethoprim)?
Mild-to-moderate infections on the eye and eyelid
Bacterial eye infection
To prevent pink eye (conjunctivitis) in newborns who might be exposed to certain sexually-transmitted infections (STIs) from their mothers during birth
What is the latest news about Polytrim (polymyxin B / trimethoprim)?
Polytrim (polymyxin B / trimethoprim) images
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References
Best studies we foundAmerican Academy of Allergy, Asthma, & Immunology. (2024). Tips for administering eye drops.
Bausch & Lomb Incorporated. (2023). Polymyxin B sulfate and trimethoprim- polymyxin b sulfate and trimethoprim sulfate solution/ drops [package insert]. DailyMed.
Centers for Disease Control and Prevention. (2024). How to treat pink eye.
Estrada, A., et al. (2016). Antibacterial antifolates: From development through resistance to the next generation. Cold Spring Harbor Perspectives in Medicine.
Mohapatra, S. S., et al. (2021). Polymyxins, the last-resort antibiotics: Mode of action, resistance emergence, and potential solutions. Journal of Biosciences.
Shah, T. J., et al. (2018). "Doctor, I have a sulfa allergy": Clarifying the myths of cross-reactivity. Ophthalmology and Therapy.
Wróbel, A., et al. (2020). Trimethoprim and other nonclassical antifolates an excellent template for searching modifications of dihydrofolate reductase enzyme inhibitors. The Journal of Antibiotics.
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