Mast cell stabilizers are often used in combination with antihistamines to treat allergic conjunctivitis or eye infection. The antihistamines help relieve itchiness while the mast cell stabilizers help to inhibit allergic mediators being released from mast cells, thus preventing allergic reactions to common allergens (substances that cause allergies).  Mast cells are white blood cells found in the immune system. Used together, the medications help relieve itching, tearing, burning, and redness.

Allergic conjunctivitis or pink eye is an eye disease that affects the conjunctiva, the eye’s mucous membrane lining the eyelid’s inner surfaces.  According to the American Academy of Allergy, Asthma, and Immunology, over 50 million Americans are affected by the condition. The common causes of allergic conjunctivitis include exposure to dust mites, some types of animals, pollen from trees, and grass. People with a history or family history of allergies are at risk of developing allergic conjunctivitis. The effect includes sneezing, runny nose, watery eyes, and red or pink itchy, puffy eyes. Although rare, allergic conjunctivitis can lead to blurry vision. While some allergies are seasonal, some may occur throughout the year. Seasonal allergies tend to occur during certain seasons, such as when pollen abounds. Those that occur throughout the year are mostly caused by indoor allergens such as dust mites.

Allergic conjunctivitis is often diagnosed via a slit-lamp exam, which reveals swollen blood vessels on the eye's surface. Further tests to confirm allergic conjunctivitis include testing specific types of white blood cells in the eye. The standard treatment for allergic conjunctivitis is usually to avoid the allergen, use cold compresses, and artificial tears. However, mast cell stabilizers belong to a range of medications that can help relieve allergic conjunctivitis symptoms. Most practitioners consider mast cell stabilizers and antihistamine combination the first line of medical treatment for allergic conjunctivitis. This combination has the advantage of being administered once a day, which means patient compliance is highly necessary.

All the topical antihistamine and mast-cell stabilizer combinations are made from ketotifen, an active ingredient. Claritin Eye, Alaway, Zaditor, Visine All Day Itch Relief, and Refresh Eye Itch Relief are examples of these combinations. These medications work faster to relieve itching and prevent itching for an extended period (about 12 hours). Elestat and Alrex, especially, are said to have a longer duration of action. They are also available over the counter. Mast cell stabilizer eye drops are also available via prescription, and these include Cromolyn, Lodoxamide, Nedocromil sodium, and Pemirolast potassium.

Administration & Dosage

Mast cell stabilizer eye drops are administered one to two times a day. However, the number of times the eye drops can be used depends on the different types. All in all, these medications generally require a patient to take the eyedrops less frequently. Some doctors advise that patients who may have a long-term allergic conjunctivitis problem should take a drug like Zaditor or Alaway once or twice every day. Those presenting with a severe case of allergic conjunctivitis should take Pataday two times per day.

Some medications can be taken to prevent symptoms from developing if patients know they are likely to get an allergy. Sodium cromoglicate is an example of a mast cell stabilizer, and it takes a few days to begin working. It does not work straight away, thus a good option for preventive purposes.

Potential Side Effects & Interactions

Potential side effects generally include blurry vision, burning, or stinging eyes when the drug is administered. These side effects may depend on the particular medication. For instance, reports indicate that generally, cromolyn sodium is well-tolerated and presents with very few adverse reactions. However, its incidence of side effects is yet to be defined.

Antihistamines, which also contain mast cell stabilizers, can cause sensitivity to light, burning, stinging, or irritation of the eye. Other side effects of this drug include headache, bad taste in the mouth, and a runny nose. Should dry eye, pain, trouble breathing, blurry vision, eye swelling, rash, severe dizziness, increased itching, or increased redness occur, the patient should contact the doctor right away.

Symptoms of Overdose

This medication is harmful and should not be swallowed. It should also be stored away from children and pets. In case of overdose and the person exhibits severe symptoms such as breathing problems or passing out, s/he should call 911 or the poison control center in America (1-800-1222).