Question: what are 2nd generation antihistamines?
Answer: Antihistamines, 2nd Generation These include brompheniramine, chlorpheniramine (Chlor-Trimeton), and diphenhydramine (Benadryl). Some 2nd generation antihistamines, such as fexofenadine (Allegra), loratadine (Claritin), and cetirizine (Zyrtec) are now available OTC without a prescription.