Main unwanted side effect of sedating antihistamines
antagonist that is devoid of effects on α-adrenergic, dopaminergic, and muscarinic receptors.
The recommended dose is 1–2 drops in each affected eye b.i.d. Peak serum concentrations are usually reached within 2 hours of dosing.
The recommended dosage is one drop every 8–12 hours.
Levocabastine absorption from the eye occurs within 1–2 hours.
Ketotifen, like azelastine, has potent nonantihistamine anti-inflammatory activity.
It inhibits mediator release from mast cells and basophils, degranulation of eosinophils and neutrophils, chemotaxis of eosinophils, leukotriene generation, and the generation of platelet-activating factor.
The drug has a plasma protein binding of approximately 65%.
The recommended dosage is one drop in each eye b.i.d. Eye drops administered regularly do not suppress histamine-induced skin wheal and flare.
Bioavailability from topical ocular administration ranges from 30% to 60%.
Steady-state plasma levels after the application of a 0.05% ophthalmic suspension one drop three times a day are 1.6 μg/l.
The half-life in plasma is approximately 3 hours and elimination is primarily through renal excretion, with 60–70% of the dose recovered in the urine as the parent drug.
Two metabolites are found in low concentrations in the urine: the mono-desmethyl and , α-adrenergic, and serotonin receptors as well.