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What causes anaphylaxis after taking antibiotics?

This Premium Q&A, reviewed and published, features a real conversation between an iCliniq user and a physician.

Patient's Query

Hi doctor,

Yesterday, I had my wisdom tooth extracted and received a prescription for Acetaminophen 300 mg and Codeine 30 mg for pain, as well as Amoxicillin 500 mg to prevent infection. I took one dose of Amoxicillin immediately after leaving the dental office, and I had no reaction for the rest of the day. Later, just before going to sleep, I took another dose of Amoxicillin along with one other Acetaminophen and Codeine.

The next morning, I woke up with an anaphylactic reaction affecting my groin and inner thighs. I am trying to determine whether the reaction was caused by Acetaminophen and Codeine, Amoxicillin, or a combination of the two. Since the pain was manageable, I decided to stop using the medication and am waiting to see if the reaction resolves. I am aware that many people are allergic to this class of antibiotics, and I am wondering if I might be as well, even though I have never had an allergic reaction before. I believe I have taken this class of antibiotics in the past, but I am not certain.

Please suggest.

Answered by Dr. Pooja Pardhi

Education:

MBBS

Professional Bio:

Dr. Pooja Pardhi is a General Physician and General Practitioner for 15 years. She completed MBBS from Government Medical College, Nagpur, in 2009 . She is also an expert in Internal Medicine. She consults patients at home, monitoring patients' conditions and wellbeing. She diagnoses and treats illnesses or ailments, does minor surgeries, and carries out tests to diagnose the condition. She is currently practicing in Mumbai.

This doctor is not available for online consultations on the platform anymore.

Hi.

Welcome to icliniq.com.

I have reviewed your query and understand your health concern.

The allergic reaction is likely due to Amoxicillin, as Acetaminophen and Codeine typically do not cause allergic reactions. I recommend stopping Amoxicillin and considering Cephalosporin as an alternative.

For the allergic reaction, I suggest taking an antihistamine twice daily for three days. Amoxicillin and other drugs in this class are known to commonly cause allergic reactions. Even though you have not experienced such a reaction before, it is possible for it to occur. I advise against using Amoxicillin in the future.

I hope this helps.

Take care.

Medically reviewed by iCliniq medical review team
Published At June 14, 2018
Reviewed At November 13, 2025

Education:

MBBS

Professional Bio:

Dr. Pooja Pardhi is a General Physician and General Practitioner for 15 years. She completed MBBS from Government Medical College, Nagpur, in 2009 . She is also an expert in Internal Medicine. She consults patients at home, monitoring patients' conditions and wellbeing. She diagnoses and treats illnesses or ailments, does minor surgeries, and carries out tests to diagnose the condition. She is currently practicing in Mumbai.

This doctor is not available for online consultations on the platform anymore.

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Education:

MBBS

Professional Bio:

Dr. Pooja Pardhi is a General Physician and General Practitioner for 15 years. She completed MBBS from Government Medical College, Nagpur, in 2009 . She is also an expert in Internal Medicine. She consults patients at home, monitoring patients' conditions and wellbeing. She diagnoses and treats illnesses or ailments, does minor surgeries, and carries out tests to diagnose the condition. She is currently practicing in Mumbai.

This doctor is not available for online consultations on the platform anymore.

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