Levocabastine is a potent, selective histamine H1-antagonist.
Antigen challenge studies performed two and four hours after initial drug instillation indicated activity was maintained for at least two hours.
In an environmental study, LIVOSTIN™ 0.05% (levocabastine hydrochloride ophthalmic suspension) instilled four times daily was shown to be significantly more effective than its vehicle in reducing ocular itching associated with seasonal allergic conjunctivitis.
After instillation in the eye, levocabastine is systemically absorbed. However, the amount of systemically absorbed levocabastine after therapeutic ocular doses is low (mean plasma concentrations in the range of 1-2 ng/mL).