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Mechanism of Action
Rescula is believed to reduce elevated intraocular pressure (IOP) by increasing the outflow of aqueous humor through the trabecular meshwork. Unoprostone isopropyl (UI) may have a local effect on BK (Big Potassium) channels and ClC-2 chloride channels, but the exact mechanism is unknown at this time.
After application to the eye, unoprostone isopropyl is absorbed through the cornea and conjunctival epithelium where it is hydrolyzed by esterases to unoprostone free acid.
A study conducted with 18 healthy volunteers dosed bilaterally with unoprostone isopropyl ophthalmic solution twice daily for 14 days demonstrated little systemic absorption of unoprostone isopropyl. The systemic exposure of its metabolite unoprostone free acid was minimal following the ocular administration. Mean peak unoprostone free acid concentration was less than 1.5 ng/mL. Little or no accumulation of unoprostone free acid was observed.
Following ocular application, unoprostone isopropyl is hydrolyzed by esterases in the cornea to its biological active metabolite, unoprostone free acid. Unoprostone free acid is further metabolized to several inactive metabolites with lower molecular weight and increased polarity via ε- or β-oxidation. No secondary conjugation is found and no significant effect on hepatic microsomal enzyme activity has been observed.
Elimination of unoprostone free acid from human plasma is rapid, with a half-life of 14 minutes. Plasma levels of unoprostone free acid dropped below the lower limit of quantitation ( < 0.25 ng/mL) 1 hour following ocular instillation. The metabolites are excreted predominately in urine.
In six (6) month randomized controlled clinical studies in patients with a mean baseline intraocular pressure of 23 mmHg, Rescula lowered intraocular pressure by approximately 3– 4 mmHg throughout the day. Rescula appeared to lower intraocular pressure without affecting cardiovascular or pulmonary function.
Last reviewed on RxList: 1/3/2013
This monograph has been modified to include the generic and brand name in many instances.
Additional Rescula Information
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