How Do Ophthalmic Antihistamines Work?

Reviewed on 5/14/2021

WHAT ARE OPHTHALMIC ANTIHISTAMINES AND HOW DO THEY WORK?

Ophthalmic antihistamines relieve eye allergy symptoms by blocking the release of histamine by mast cells, a type of immune cell. Mast cells release histamine when they detect foreign substances in the body. Histamine causes swelling and inflammation. The blood vessels in your eyes swell and your eyes get red, teary and itchy.

Mast cells are part of the front-line immune system defense against antigens. Mast cells are present in mucous and epithelial tissue that line the surface of all organs. In the eyes, mast cells are abundant in the conjunctiva, the clear mucous membrane that forms a protective layer over the eyes and the inner surfaces of the eyelids.

In addition to histamine, mast cells also release other inflammatory proteins such as cytokines and chemokines which activate other types of immune cells such as eosinophils which further promote inflammation. Blocking the activity of histamines, therefore, is effective in controlling inflammation.

Ophthalmic antihistamines bind to certain proteins at the inflammation site known as H1-receptors to prevent allergic response. Ophthalmic antihistamines work in the following ways:

Block the release of histamine by mast cells

  • Inhibit the activation of eosinophils
  • Inhibit the movement of mast cell and eosinophil to the inflammation site
  • Reduce the permeability of blood vessels and prevent leakage of inflammatory substances into the inflammation site

HOW ARE OPHTHALMIC ANTIHISTAMINES USED?

Ophthalmic antihistamines are solutions administered in the eyes to relieve symptoms of allergic conjunctivitis. Allergic conjunctivitis is inflammation of the conjunctiva caused by a reaction to allergens such as pollen, dust, dander and mold spores.

SLIDESHOW

Pink Eye (Conjunctivitis) Symptoms, Causes, Treatments See Slideshow

WHAT ARE SIDE EFFECTS OF OPHTHALMIC ANTIHISTAMINES?

Side effects of ophthalmic antihistamines may include the following:

Ocular side effects:

The information contained herein is not intended to cover all possible side effects, precautions, warnings, drug interactions, allergic reactions, or adverse effects. Check with your doctor or pharmacist to make sure these drugs do not cause any harm when you take them along with other medicines. Never stop taking your medication and never change your dose or frequency without consulting your doctor.

WHAT ARE DRUG NAMES OF OPHTHALMIC ANTIHISTAMINES?

Generic and brand names of some ophthalmic antihistamines include:

References
https://reference.medscape.com/drugs/antihistamines-ophthalmic

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5010431/

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