|Systematic (IUPAC) name|
|Trade names||Patanol and others|
|Routes||Ophthalmic, intranasal, oral|
|ATC code||S01 R01|
|Mol. mass||337.412 g/mol|
|(what is this?)|
Olopatadine hydrochloride is an antihistamine (as well as anticholinergic and mast cell stabilizer), sold as a prescription eye drop (0.2% solution, 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 Patanol (or Opatanol in some countries). A decongestant nasal spray formulation is sold as Patanase, which was approved by the FDA on April 15, 2008. It is also available as an oral tablet in Japan under the tradename Allelock, manufactured by Kyowa Hakko Kogyo.
It should not be used to treat irritation caused by contact lenses. The usual dose for Patanol is 1 drop in each affected eye 2 times per day, with 6 to 8 hours between doses.
There is potential for Olopatadine as a treatment modality for steroid rebound (red skin syndrome.) 
Olopatadine was developed by Kyowa Hakko Kogyo.
Some known side effects include headache (7% of occurrence), eye burning and/or stinging (5%), blurred vision, dry eyes, foreign body sensation, hyperemia, keratitis, eyelid edema, pruritus, asthenia, sore throat (pharyngitis), rhinitis, sinusitis, and taste perversion.
- Drugs.com, Alcon's Patanase Nasal Spray Approved by FDA for Treatment of Nasal Allergy Symptoms
- Kyowa Hakko Kogyo Co., Ltd. (2007). "ALLELOCK Tablets 2.5 & ALLELOCK Tablets 5 (English)" (PDF). Retrieved 2008-08-10.
- Tamura T, Matsubara M, Hasegawa K, Ohmori K, Karasawa A. (2005). "Olopatadine hydrochloride suppresses the rebound phenomenon after discontinuation of treatment with a topical steroid in mice with chronic contact hypersensitivity.".
- Kyowa Hakko Kogyo Co., Ltd. (2002). "Company History". Company Information. Kyowa Hakko Kogyo Co., Ltd. Retrieved 16 September 2010.