Allergist and Immunologist Questions Antihistamines

Do antihistamines cause excessive sleepiness?

I have been taking antihistamines for my dog allergy (I have two, but I only take antihistamines) and it makes me feel very sleepy and drowsy. Is it a normal effect of these medicines?

3 Answers

Yes, unfortunately in some patients antihistamines can cause sedation. Not all of them do that so it will be important for you to try different preparations and see how you respond to them. You can also try and take them at bedtime - for a lot of patients that can help a lot.
Yes. This is a normal effect. You can switch to another type of antihistamine such as fexofenadine or loratadine.
Yes, antihistamines can cause drowsiness. Benadryl especially causes this. The newer antihistamines (second generation) such as Claritin or Allegra, have less of a tendency to do this.

Respectfully submitted,

Margaret L. Soderberg, M.D., FACAAI