# BEWARE OF ANTIHISTAMINES!



## Cheryl1967 (Apr 19, 2012)

I just wanted to mention that in the past I have taken antihistamines, even premenstrual OTC medicine and it caused me to have violent diarrhea. I know a lot of people take medications for allergies whether it be OTC or prescription and believe it or not histamine also comes from the gut so alterations in histamine levels can contribute to severe attacks of diarrhea. It might be worth looking into if any of you suffer from IBS D


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## Kathleen M. (Nov 16, 1999)

This seems like an unusual reaction to anti-histamines.Usually the role of histamine in the gut (other than make sure you release acid when you eat) is to cause diarrhea (kind of like a sneeze for the gut), and more commonly blocking that can reduce diarrhea.That being said, people can be allergic to any medication (even anti-allergy medication) or have paradoxical reactions (where the drug increases that which they would normally block)


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## KJL (Mar 19, 2012)

I take them daily for allergies (prescribed).but I have IBS-C, not D I guess everyone is different.


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## leebe20 (Aug 26, 2011)

Cheryl1967 said:


> I just wanted to mention that in the past I have taken antihistamines, even premenstrual OTC medicine and it caused me to have violent diarrhea. I know a lot of people take medications for allergies whether it be OTC or prescription and believe it or not histamine also comes from the gut so alterations in histamine levels can contribute to severe attacks of diarrhea. It might be worth looking into if any of you suffer from IBS D


Sorry to hear of your Severe reaction, But its quite unusual for Anti-histamines to cause diarrhea My doctor told me it can happen but its a rare side effect or they have a rare allergy to the drug.


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## nicoler (Aug 18, 2012)

Sounds like you have developed an allergy to the antihistamines. I live in the southern part of the US and take zyrtec daily (twice daily from Jan-May)and benadryl when that isn't enough. The last time I went to the GI doc he said if I didn't already take these he might prescribe an antihistamine because they have been found to help with histamine induced IBS. Especially in women. Sorry they give you so much trouble. Just so you know for future reference Pepcid AC is an antihistamine too. Was told to take it in addition to benadryl after a wasp sting that nearly caused anaphylaxis.


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