Key takeaways
Olopatadine (Pataday) and ketotifen (Zaditor) are both over-the-counter antihistamine eye drops used to treat allergy-related eye symptoms, but they have some differences. Olopatadine can be used by people as young as 2 years old, while ketotifen is for those 3 years and older. Olopatadine comes in different strengths and can be used once or twice daily depending on the formulation, whereas ketotifen is typically used twice daily. Olopatadine may work faster to relieve symptoms and has fewer side effects compared to ketotifen. Both medications require you to remove contact lenses before use and wait at least 10 minutes before putting them back in. Ketotifen should not be used for more than 3 days in a row without consulting a provider, while olopatadine can be used for year-round allergies. Both medications are available as lower-cost generics.
