November 30, 2015
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"What are allergies?

Allergies occur when the body's immune system responds to a substance it considers an "invader." Substances that provoke the immune system into an allergic response are known as allergens. There is no such thing as a"...



Mechanism of Action

Olopatadine is a mast cellstabilizer and a histamine H1 antagonist. Decreased chemotaxis and inhibition of eosinophil activation has also been demonstrated.


Systemic bioavailability data upon topical ocular administration of PATADAY™ (olopatadine hydrochloride ophthalmic solution) solution are not available. Following topical ocular administration of olopatadine 0.15% ophthalmic solution in man, olopatadine was shown to have a low systemic exposure. Two studies in normal volunteers (totaling 24 subjects) dosed bilaterally with olopatadine 0.15% ophthalmic solution once every 12 hours for 2 weeks demonstrated plasma concentrations to be generally below the quantitation limit of the assay ( < 0.5 ng/mL). Samples in which olopatadine was quantifiable were typically found within 2 hours of dosing and ranged from 0.5 to 1.3 ng/mL. The elimination half-life in plasma following oral dosing was 8 to 12 hours, and elimination was predominantly through renal excretion. Approximately 60 - 70% of the dose was recovered in the urine as parent drug. Two metabolites, the mono-desmethyl and the N-oxide, were detected at low concentrations in the urine.

Clinical Studies

Results from clinical studies of up to 12 weeks duration demonstrate that PATADAY™ (olopatadine hydrochloride ophthalmic solution) solution when dosed once a day is effective in the treatment of ocular itching associated with allergic conjunctivitis.

Last reviewed on RxList: 1/27/2011
This monograph has been modified to include the generic and brand name in many instances.

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