Please describe the medication: patanol (olopatadine)?

Antihistamine: It is an antihistamine and mast cell stabilizer used to reduce allergic symptoms. Because of its anticholinergic effects, side effects include headache, blurred vision, eye burning and dryness, sore throat and taste changes (cf wikipedia).

Conjunctivitis: Patanol, generic name is olopatadine. It is used in the eye to treat conjunctivitis that is caused by allergies. It works by having an antihistamine effect (much like Benadryl (diphenhydramine) when it's used to treat allergies). Patanol, when used as directed is generally very safe.