| Indication |
For the prevention of itching associated with allergic conjunctivitis. |
| Pharmacodynamics |
Epinastine is an antihistamine and an inhibitor of histamine
release from the mast cell for topical administration to the eyes.
Epinastine is indicated for the prevention of itching associated with
allergic conjunctivitis. Epinastine is a topically active, direct H1-receptor
antagonist and an inhibitor of the release of histamine from the mast
cell. Epinastine is selective for the histamine H1-receptor and has affinity for the histamine H2 receptor. Epinastine also possesses affinity for the a1-, a2-, and 5-HT2
-receptors. Epinastine does not penetrate the blood/brain barrier and,
therefore, is not expected to induce side effects of the central nervous
system. |
| Mechanism of action |
Epinastine has a multiaction effect that inhibits the allergic
response in 3 ways: 1. stabilizes mast cells by preventing mast cell
degranulation to control the allergic response, 2. prevents histamine
binding to both the H1- and H2-receptors to stop itching and
provide lasting protection, and 3. prevents the release of
proinflammatory chemical mediators from the blood vessel to halt
progression of the allergic response. |
| Absorption |
The absolute bioavailability of epinastine is about 40%. |
| Volume of distribution |
Not Available |
| Protein binding |
64% |
| Metabolism |
Mainly excreted unchanged, less than 10% metabolized. |
| Route of elimination |
Epinastine is mainly excreted unchanged. The renal elimination is mainly via active tubular secretion. |
| Half life |
12 hours |
| Clearance |
- 56 L/hr [patients with allergic conjunctivitis receiving one drop
of ELESTAT® ophthalmic solution in each eye twice daily for seven days]
|
| Toxicity |
Not Available |
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