Besides doxylamine & diphenhydramine, what other otc antihistamines cause drowsiness? without a prescription.

First generation: Antihistamines, most cause drowsiness, second and third generations antihistamines, taken once day, usually don't cause drowsiness, loratadine, desloratadine, cetirizine and levocetirizine,

Allegra (fexofenadine): All antihistamines especially the first generation ones (benadryl, bromchlorpheniramine, CTM) can cause drowsiness when given in sufficient doses. Zyrtec (cetirizine) at the recommended dose and Loratadine at 2x the recommended dose can cause drowsiness in some people. The least likely AH to cause drowsiness is fexofenadine (Allegra).