Polymyxin B and trimethoprim ophthalmic and Sulfamethoxazole and trimethoprim interaction

Polymyxin B and trimethoprim ophthalmic and Sulfamethoxazole and trimethoprim: the Polymyxin B and trimethoprim ophthalmic prescribing label describes an interaction that usually calls for monitoring, a dose change, or spacing the doses.

Moderate

Usually manageable with monitoring or a dose change. Tell your pharmacist you take both.

What the FDA labels say

From the Polymyxin B and trimethoprim ophthalmic (Polymyxin B Sulfate and Trimethoprim) label · effective 2026-01-27

Moderate

In a separate survey, Brumfitt and Pursell also found no congenital abnormalities in 35 children whose mothers had received oral trimethoprim and sulfamethoxazole at the time of conception or shortly thereafter.

Precautionsnames Sulfamethoxazole and trimethoprimView label on DailyMed
Minor

While there are no large well-controlled studies on the use of trimethoprim in pregnant women, Brumfitt and Pursell, in a retrospective study, reported the outcome of 186 pregnancies during which the mother received either placebo or oral trimethoprim in combination with sulfamethoxazole.

Precautionsnames Sulfamethoxazole and trimethoprimView label on DailyMed
Minor

The incidence of congenital abnormalities was 4.5% (3 of 66) in those who received placebo and 3.3% (4 of 120) in those receiving trimethoprim and sulfamethoxazole.

Precautionsnames Sulfamethoxazole and trimethoprimView label on DailyMed

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Not medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.