Drug allergy reaction occurs not until the second shot

Written by: Dr. Óscar Cáceres Calle
Edited by: Top Doctors®

Contrary to what we are accustomed to think, the first time a drug is consumed there is no allergy reaction. To develop it, it is necessary that the immune system prepare and develop the response to deal with that medicine. That is why the allergic reaction to a product can be given from the second contact with it, although it is a mistake to think that if a medication has been consumed frequently and has never been misused, we will never have an allergic reaction to it.

The one that most determines a drug allergy is the repeated contact with these, in addition to other factors such as genetic background or having other allergies. The more medication you use, the more likely you are to have an allergic reaction. Non-steroidal anti- inflammatories (such as Ibuprofen ), beta-lactam antibiotics (such as Penicillin ) or iodinated contrasts, among others, are the most allergenic medications we know.



Hazards and treatment

The most dangerous allergic reaction is anaphylaxis, which affects two or more organs and progresses rapidly, putting people's lives at risk. Other frequent reactions are angioedema , urticaria , digestive symptoms, respiratory symptoms such as asthma and rhinitis.

In case of suffering allergic reactions, the patient must undergo alternative treatments. Those allergic to beta-lactams should switch to other groups of antibiotics that have the same spectrum of action and serve the same bacteria. Those allergic to non-steroidal anti-inflammatory drugs usually tolerate paracetamol and use corticosteroids and selective COX-2 inhibitors. There are also drug desensitizations, although they are usually done in extreme cases.


*Translated with Google translator. We apologize for any imperfection

By Dr. Óscar Cáceres Calle
Allergy & Immunology

*Translated with Google translator. We apologize for any imperfection

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