Olodin Mechanism of Action

Pharmacology: Pharmacodynamics: Olopatadine is a potent selective antiallergic/antihistaminic agent that exerts its effects through multiple distinct mechanism of action. It antagonises histamine (the primary mediator of allergic response in humans) and prevents histamine induced inflammatory cytokine production by human conjunctival epithelial cells. Data from in vitro studies suggest that it may act on human conjunctival mast cells to inhibit the release of pro-inflammatory mediators. In patients with patent nasolacrimal ducts, topical ocular administration of olopatadine was suggested to reduce the nasal sign and symptoms that frequently accompany seasonal allergic conjunctivitis. It does not produce a clinically significant change in pupil diameter.
Pharmacokinetics: Absorption: Olopatadine ophthalmic solution is absorbed systemically, as are other topically administered medicinal products. However, systemic absorption of topically applied olopatadine is minimal with plasma concentration ranging from below the assay quantitation limit up to 1.3 ng/ml. These concentrations are 50-to 200-fold lower than those following well tolerated oral doses.
Elimination: The half-life of olopatadine in plasma was approximately eight to 12 hours, and elimination was predominantly through renal excretion. Approximately the dose was recovered in the urine as active substance. Two metabolites, the mono-desmethyl and the N-oxide, were detected at low concentration in the urine.
Since olopatadine is excreted in urine primarily as unchanged active substance, impairment of renal function alters the pharmacokinetics of olopatadine with peak plasma concentrations 2.3-fold greater in patients with severe renal impairment compared to healthy adults.
Following a 10mg oral dose in patients undergoing haemodialysis (with no urinary output), plasma olopatadine concentration were significantly lower on the haemodialysis day than on non-haemodialysis day suggesting olopatadine can be removed by haemodialysis.
A renal impairment after oral dosing of olopatadine has been performed in patients with severe renal impairment. The results indicate that a somewhat higher plasma concentration can be expected with olopatadine in this population. Since plasma concentration following topical ocular dosing of olopatadine are 50-to 200-fold lower than after well-tolerated oral doses, dose adjustment is not expected to be necessary in the elderly or in the renally impaired population. Liver metabolism is a minor route of elimination. Dose adjustment is not expected to be necessary with hepatic impairment.