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A member asked:

Does antihistamine make you drowsy?

A doctor has provided 1 answer
Dr. Maziar Rezvani answered

Specializes in Allergy and Immunology

Older ones do: First generation antihistamines (benadryl, clor-pheramine, atarax) cross the blood brain barrier and cause lethargy. Second generation (allegra, claritin, zyrtec, xyzal, (levocetirizine) clarinex) cause the blood brain barrier at a much lesser amount and more targeted to the h1 receptor.

Dr Ali and another doctor agreed

Answered 9/16/2019

5.7k views

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Related Questions

A member asked:

Do histamines (not antihistamine medications) make you drowsy? Antihistamines (no decongestants added) seem to make me more alert when allergies flare

A doctor has provided 1 answer

A member asked:

What is good otc antihistamine to take for someone have asthma..I take clarity sometimes but it makes me drowsy and sleepy..is allegra (fexofenadine) better?

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A member asked:

Besides doxylamine & diphenhydramine, what other OTC antihistamines cause drowsiness? Without a prescription.

4 doctors weighed in across 2 answers

A member asked:

Bitten by unknown insect. Redness and swelling to forarm. Marked with pen and doubled in size over 36hrs. Taking non drowsy antihistamines and icing?

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A member asked:

Am thinking I may be allergic to our English bulldog. Which is the safest/most effective Rx or OTC antihistamine that's least likely to cause drowsiness and can be used daily? Zyrtec claims to be non-drowsy, but it makes me very sleepy?

A doctor has provided 1 answer

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