Key takeaways
Loratadine (Claritin) and cetirizine (Zyrtec) are both second-generation antihistamines. They treat allergies and are much less likely to cause drowsiness compared to first-generation antihistamines, such as diphenhydramine (Benadryl). Lortidine and cetirizine are both effective, but cetirizine usually starts working faster. And although cetirizine isn’t known to cause extreme drowsiness, it’s still more likely than loratadine to cause drowsiness.
