CLINICAL PHARMACOLOGY
Lodoxamide tromethamine is a mast cell stabilizer that inhibits the in vivo Type I immediate hypersensitivity reaction. Lodoxamide therapy inhibits the increases in cutaneous vascular permeability that are associated with reagin or IgE and antigen-mediated reactions.
In vitro studies have demonstrated the ability of lodoxamide to stabilize rodent mast cells and prevent antigen-stimulated release of histamine. In addition, lodoxamide prevents the release of other mast cell inflammatory mediators (i.e., SRS-A, slow-reacting substances of anaphylaxis, also known as the peptidoleukotrienes) and inhibits eosinophil chemotaxis. Although lodoxamide's precise mechanism of action is unknown, the drug has been reported to prevent calcium influx into mast cells upon antigen stimulation.
Lodoxamide has no intrinsic vasoconstrictor, antihistaminic, cyclooxygenase inhibition, or other anti-inflammatory activity.
The disposition of 14C-lodoxamide was studied in six healthy adult volunteers receiving a 3 mg (50 μCi) oral dose of lodoxamide. Urinary excretion was the major route of elimination. The elimination half-life of 14C-lodoxamide was 8.5 hours in urine. In a study conducted in twelve healthy adult volunteers, topical administration of ALOMIDE® (lodoxamide tromethamine ophthalmic solution) 0.1%, one drop in each eye four times per day for ten days, did not result in any measurable lodoxamide plasma levels at a detection limit of 2.5 ng/mL.
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