Key takeaways
Olopatadine (Pataday) and cetirizine (Zyrtec) are both antihistamines used to treat allergy symptoms, but they have some key differences. Olopatadine is an eye drop used to relieve eye itching and redness caused by allergies, while cetirizine is taken orally to treat a broader range of allergy symptoms, including runny nose and watery eyes. Olopatadine is available over-the-counter and is used once or twice daily, depending on the strength. Cetirizine is also available over-the-counter and comes as tablets, chewable tablets, or liquid solutions. Cetirizine is typically taken once a day. Olopatadine can cause blurry vision and should not be used with contact lenses immediately after applying the drops, whereas cetirizine can cause drowsiness and is not recommended to be taken with alcohol. Additionally, cetirizine is safe for use during pregnancy, while you should consult your provider before using olopatadine if you're pregnant.
