This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology, Subject name: Pharmacology
[{'content': 'Olopatadine is: \nSelect and explain. \nA. Mast cell stabilizer, B. Anti-histamine, C. Both mast cell stabilizer and anti histamine, D. None of the above', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ref: Clinical Oculor Pharmacology, 1st ed. pg. 257* Olopatadine hydrochloride is an antihistamine (as well as anticholinergic and mast cell stabilizer)* It is used as eye drop to treat itching associated with allergic conjunctivitis.* Side effects include headache, eye burning and/or stinging, blurred vision, dry eyes, foreign body sensation, hyperemia, keratitis and taste perversion.', 'role': 'assistant'}]