I get headaches from allergies. Can I take Claritin (loratadine) and zyrtec at the same time? Claritin (loratadine) didn't work alone when I traveled away from home.

Yes, but. Both Claritin (loratadine) and zyrtec (cetirizine) are new generation antihistamines. While there is no harm to using them together, there is likely no added benefit either. The most effective treatment for nasal allergies is the topical nasal steroid sprays such as qnasl, flonase, veramyst, nasonex, (mometasone) etc if a person doesn't have relief with an antihistamine alone.