Polymyxin B and trimethoprim eye drops (Polytrim®) are a prescription antibiotic combination commonly prescribed to treat bacterial eye infections such as conjunctivitis (“pink eye”) and blepharoconjunctivitis. Polymyxin B works by disrupting the outer cell membrane of certain bacteria, while trimethoprim blocks bacterial folic acid synthesis, preventing growth. Together, this dual mechanism provides broad-spectrum antibacterial coverage to help clear infection and relieve associated symptoms such as redness, discharge, and irritation.
How to Use
Typically prescribed as 1 drop in the affected eye(s) every 3 hours while awake, up to 6 times daily, for 7 to 10 days.
Wash hands before use and avoid touching the dropper tip to the eye or any surface to prevent contamination.
Tilt the head back, pull down the lower eyelid, and instill a drop into the conjunctival sac. Close the eye gently for 1 to 2 minutes to improve absorption.
Continue using the drops for the full duration prescribed, even if symptoms improve earlier, to ensure the infection is fully treated.
If multiple eye medications are prescribed, wait at least 5 minutes between administering each one.
Important Notes and Warnings
For ophthalmic use only; do not ingest.
Common side effects may include mild eye burning, stinging, redness, or temporary blurred vision.
Serious allergic reactions are rare but possible; discontinue and seek medical care if swelling, rash, or worsening irritation occurs.
This medication is not effective for viral or fungal eye infections. Using it inappropriately may contribute to antibiotic resistance.
Contact lenses should not be worn during treatment of an active infection; resume use only after the infection has cleared and with provider approval.
Inform your healthcare provider if you have a history of eye surgery, chronic eye conditions, or medication allergies before starting treatment.
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