how to choose an antihistamine
Patients will be asking how to choose an antihistamine... especially with all the new ads for OTC Zyrtec.
Older OTCs like diphenhydramine (Benadryl, others), etc are classified as "first generations." Newer OTCs Zyrtec (cetirizine) and loratadine (Claritin, etc), and Rx agents like Allegra (fexofenadine), etc, are "second generations."
Effectiveness. First generations usually work as well as second- generation antihistamines for allergy symptoms. But drowsiness and dry mouth often make them less desirable.