Patanol (Olopatadine)
Patanol™
Classification:
Ophthalmic Agents
- Ophthalmic Antiinflammatory Agents
Description: Olopatadine is a topical ophthalmic agent for the prevention of ocular pruritus due to allergic conjunctivitis. It is the first ophthalmic agent with both antihistamine and mast cell stabilizing effects. Although no comparative studies have been performed, olopatadine may be a more potent mast cell stabilizer than cromolyn. Olopatadine has a low incidence of adverse reactions and may be better tolerated than ketorolac and levocabastine. Olopatadine also has a rapid onset of action and a long duration of action which allows for twice daily dosing. A once daily ophthalmic formulation of olopatadine is being investigated. A nasal spray is also being evaluated for seasonal allergic rhinitis. Olopatadine (Patanol™) was FDA approved December 16, 1996.
Mechanism of Action: Olopatadine exhibits two distinct mechanisms of action. Olopatadine inhibits histamine release from mast cells and is a relatively selective antagonist of H1-receptors. As a result, olopatadine prevents type 1 immediate hypersentivity reactions. Administration of olopatidine relieves the ocular pruritus associated with allergic conjunctivitis. Olopatadine does not act upon alpha-adrenergic, dopaminergic, type 1 or type 2 muscarinic, or serotonergic receptors.
Pharmacokinetics: Olopatadine is administered topically to the eye. Following topical ocular administration, plasma concentrations of olopatadine were in the range of 0.5 - 1.3 ng/ml within 2 hours of dosing, however, plasma concentrations were undetectable after 2 weeks of dosing in normal volunteers. The distribution of olopatadine following systemic absorption is unknown. Two metabolites, the mono-desmethyl and the N-oxide, have been identified and detected at low concentrations in the urine. Excretion is primarily via the urine with approximately 60 - 70% of a dose recovered as unchanged olopatadine. The plasma elimination half-life is approximately 3 hours.
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[ Revised 4/4/2004 6:33:00 PM ]
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