Key takeaways
Olopatadine (Pataday) and azelastine (Astelin) are both antihistamines used to treat allergy symptoms, but they differ in their application and specific uses. Olopatadine is an over-the-counter eye drop used for relieving eye itching and redness due to allergies, while azelastine is a prescription nasal spray that treats nasal symptoms like a runny or stuffy nose. Olopatadine is available in three strengths (0.1%, 0.2%, and 0.7%) and is typically applied once or twice daily, depending on the strength. Azelastine comes in two strengths (0.1% and 0.15%) and is usually sprayed into the nostrils twice a day. Olopatadine is available over the counter, whereas azelastine requires a prescription, although the 0.15% strength is also available over the counter. Common side effects of olopatadine include blurry vision and dry eye, while azelastine may cause a bitter taste, headache, and sleepiness. Additionally, azelastine can interact with alcohol and other medications that cause drowsiness, increasing the risk of sleepiness and difficulty concentrating.
