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Locust Grove, VA
A 19-year-old female asked:

How long does it take septra (sulfamethoxazole and trimethoprim) to work?. i havnt taken it three days. tomorrow will be my third. im still feeling alittle pain.? im done with pyridium.

1 doctor answer1 doctor weighed in
Dr. Dan Fisher
Internal Medicine 28 years experience
48 hours?: Starts killing right away, but sx may remain for a few days. A slight discomfort is still possible at 48 hours. Generally should continue to get better. Return of symptoms indicates a resistent organism or re-infection.
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Last updated Apr 18, 2021

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