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A member asked:

How long can an allergic reaction take to show up on penicillin based anibiotics?

A doctor has provided 1 answer

Depends: It depends on the individual. If you've never had a reaction, the first reaction may take several days of therapy to show up. If you've had a previous reaction, the next reaction will usually show up sooner, and greater, than the first reaction, so use caution if you've had a previous reaction.

Answered 7/9/2018

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I am allergic to Ceftin, Cipro, Macrobid, Sulfa, penicillin, floxin and Biaxin. My doctor says I have an UTI but she can't prescribe anything because of my allergies. She says drink lots of water. Isn't there some antibiotic I can take?

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