Olopatadine

Overview
Olopatadine hydrochloride is an antihistamine and mast cell stabilizer, sold as a prescription eye drop (0.2% solution, trademark Pataday (or Patanol S in some countries), manufactured by Alcon). It is used to treat itching associated with allergic conjunctivitis (eye allergies). Olopatadine hydrochloride 0.1% is sold as trademark Patanol (or Opatanol in some countries).

It should not be used to treat irritation caused by contact lenses. The usual dose for trademark Pataday is 1 drop in each affected eye once a day. The usual dose for trademark Patanol is 1 drop in each affected eye 2 times per day, with 6 to 8 hours between doses.

Its side effects may include headaches (7% of occurrence) burning and stinging (5%), dry eye, foreign body sensation, hyperemia, keratitis, lid edema, pruritus, asthenia, cold syndrome, pharyngitis, rhinitis, sinusitis, and taste change.