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A 40-year-old member asked:

How long after taking a medicine can an allergic reaction occur?

1 doctor answer1 doctor weighed in
Dr. Gary Steven
Pediatric Allergy and Asthma 31 years experience
Varies: If severely allergic, symptoms such as itching, hives, or wheezing can start immediately, or may develop 30 minutes to 4 hours after taking it. Milder reactions, such as rash, may not start for several days after starting he medication or, as is often the case with antibiotics, not until the second or third time you take it.

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Similar questions

Hillman, MN
A 30-year-old female asked:

How long dose it take to have an allergic reaction to a medication if it is you're first time taking the medication?

1 doctor answer2 doctors weighed in
Dr. Ronald Krauser
A Verified Doctoranswered
Rheumatology 53 years experience
Usually forever: It is very rare to have an allergic reaction the first time one takes a medication.
Dr. Gregory Gilbert
Emergency Medicine 24 years experience
Until the next time you take the medication! ;-)
May 30, 2014

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