Mast Cell Stabilizers – Types, Conditions Treated, Side Effects

Mast Cell Stabilizers

Also called: Lodoxamide, Cromolyn Sodium, Nedocromil

Reviewed By:
Marc J. Sicklick, M.D., FAAAAI, FACAAI


Mast cell stabilizers are medications used to combat allergy symptoms and allergic asthma. The drugs reduce or prevent allergy symptoms (e.g., swelling, itching, runny nose) when taken regularly. While they have very few side effects, they are not as effective as antihistamines, and they take longer to work.

The medications are taken regularly to treat a variety of allergy symptoms and prevent asthma attacks due to an allergic cascade. Many types of mast cell stabilizers also treat inflammation, reducing swelling or constricted airways to restore normal breathing. The medications usually work for four to eight hours, and must be taken regularly up to two to four weeks for full effect.

The medication is available in several different forms, including:

  • Inhaled treatments (e.g., inhaler, nebulizer)
  • Ophthalmic (related to the eye) treatments (e.g. eye drops)
  • Nasal treatments (e.g., nasal spray)
  • Oral treatments (e.g., pills, liquid)

There are generally few side effects associated with mast cell stabilizers, and those effects are usually mild. This makes the drug useful for individuals with many types of pre-existing conditions, as well as the elderly and children. Children as young as 2 can safely use some forms of mast cell stabilizers.

About mast cell stabilizers

Mast cell stabilizers are a class of medication used to prevent or treat inflammation in individuals with allergies and some types of asthma. These medications generally have fewer and milder side effects than antihistamines, but they also take longer to work and are not as effective in relieving symptoms.

Mast cell stabilizers are usually taken continuously over a period of time to lessen the severity of allergy or asthma reactions. Like antihistamines, mast cell stabilizers work by interrupting the allergic cascade to prevent or reduce symptoms.

Mast cells are a type of white blood cell that plays a key role in allergic reactions. When an allergen enters the body and is encountered by the immune system, the allergen stimulates the release of antibodies that attach themselves to mast cells. On any subsequent contact with the allergen, the antibodies will trigger the mast cells to release histamine and other chemicals which are directly responsible for causing symptoms (e.g., swelling, itching, runny nose).

Mast cell stabilizers work by stopping mast cells from degranulating (releasing their chemicals). By interfering with this critical stage of the allergic cascade, the medication prevents the release of the inflammatory chemical histamine and other mediators of allergy and asthma. Mast cell stabilizers are only effective if they are already present in the body when an allergic reaction is triggered. 

Mast cell stabilizers usually last four to eight hours and cannot effectively treat symptoms unless they have been taken regularly for two to four weeks. While antihistamines and corticosteroids are both successful at treating early phase allergic reactions (occurring within minutes of exposure to the allergen), neither are considered effective at treating late phase reactions (occurring three to 12 hours after exposure). Mast cell stabilizers are effective at preventing late phase reactions.

Asthma attacks that occur as a result of an allergic reaction can be successfully treated with mast cell stabilizers. Although mast cell stabilizers are effective at managing mild persistent asthma, moderate or severe persistent asthma is more effectively managed with mid to high-dose inhaled corticosteroids.

Mast cell stabilizers are most frequently used by individuals who need to limit their exposure to side effects. This may include children, the elderly or individuals with medical conditions that can be complicated by side effects.

Types and differences of mast cell stabilizers

Mast cell stabilizers are available in several different forms, and each is designed for a specific purpose. These include:

  • Ophthalmic (related to the eye) treatments (e.g., eye drops). Used to treat the itching in the eyes commonly associated with some allergies, as well as redness, tearing and burning. This type of mast cell stabilizer is available only by prescription. Some contain antihistamines, as well as mast cell stabilizers to treat and prevent eye allergies.

  • Nasal treatments (e.g., nasal spray). Used to treat sneezing, wheezing, runny nose and other symptoms associated with seasonal or chronic hay fever (allergic rhinitis). This type of mast cell stabilizer is available over-the-counter.

  • Inhaled treatments (e.g., inhaler). Used to prevent the symptoms of asthma. Available only by prescription.

  • Oral treatments (e.g., capsule, liquid). Usually designed to treat the symptoms of mastocytosis (rare condition caused by an overabundance of mast cells in the body). Available only by prescription.

Types of mast cell stabilizers include:

Generic NameBrand Name(s)
azelastineAstelin, Optivar
cromolynCrolom, Intal, Gastrocrom, Nasalcrom
nedocromilAlocril, Nedocromil Inhaler, Tilade

Conditions treated with mast cell stabilizers

Mast cell stabilizers are prescribed for a variety of conditions, including:

  • Allergies. Exaggerated or inappropriate reaction of the immune system to any substance that in most people causes no symptoms. Mast cell stabilizers help reduce many of the symptoms associated with some allergic conditions, including:

    • Allergic rhinitis (hay fever). Inflammation of the mucous membrane that lines the nose due to an allergic reaction to pollen, dust, dust mites or other airborne substance. Mast cell stabilizer nasal sprays are available to prevent the symptoms associated with this condition, including runny, itchy or stuffy nose and sneezing.

    • Allergic conjunctivitis. Inflammation of the tissue lining the inside of the eyelid (conjunctiva), caused by an allergic reaction. Mast cell-stabilizing eye drops are available to prevent itchiness associated with this condition.

    • Allergic sinusitis. Inflammation of the lining of the sinus cavities in the face caused by an allergic reaction. Mast cell-stabilizing nasal sprays are available to treat this condition.

  • Allergic asthma. Condition in which the airways become blocked or narrowed as the result of an allergic reaction. Mast cell stabilizers reduce or prevent symptoms, such as shortness of breath and difficulty breathing.

  • Mastocytosis. Group of disorders caused by the presence of too many mast cells in a person’s body. Mast cell stabilizers help reduce the number of mast cells.

Conditions of concern with mast cell stabilizers

Certain forms of mast cell stabilizers may not be advised for patients with some conditions. Patients with any of the following conditions should discuss the benefits and risks of mast cell stabilizer use with their physicians:

  • Kidney disease. This condition may affect the concentration of medication in the body, increasing the effects of the medication. It is of particular concern for nasal sprays and oral treatments (pills and liquids).

  • Liver disease. This condition may interfere with the concentration of medication in the body.

  • Polyps (growths in the nose).  Obstructions of the nasal passageway may prevent mast cell stabilizer nasal sprays from working effectively.

  • Heart disease or abnormal heartbeat. The propellants used in the aerosol form (inhalers) of mast cell stabilizers can worsen these conditions.

  • High blood pressure. This condition can become exacerbated when using oral mast cell stabilizers (e.g., pills, liquids).

  • Eye infections. Mast cell stabilizer eye drops can interfere with the treatment of eye infections.

In addition, some people may be allergic to mast cell stabilizers, though this is rare. Patients should not use a mast cell stabilizer if they are allergic to any of its ingredients.

Potential side effects of mast cell stabilizers

Potential side effects of mast cell stabilizers include:

  • Coughing
  • Throat irritation
  • Headache
  • Nausea
  • Vomiting
  • Dizziness
  • Drowsiness
  • Skin rashes
  • Spasms in the bronchial tubes (inhaled form)
  • Bad taste in the mouth
  • Burning or stinging in nose and subsequent sneezing (nasal form)
  • Nasal inflammation (nasal and ophthalmic forms)
  • Diarrhea (oral form)
  • Burning or stinging of the eyes (ophthalmic form)

Other, more serious side effects are possible, though rare. These include:

  • Difficulty swallowing
  • Difficulty breathing(e.g., wheezing)
  • Shortness of breath
  • Low blood pressure
  • Chest pain or tightness
  • Swelling of the lips, face, mouth, throat or eyelids (angioedema)
  • Muscle pain
  • Blurred vision (ophthalmic form)
  • Photophobia (ophthalmic form)

Anyone experiencing these side effects should contact their physician immediately. Patients should also consult their physician if their existing symptoms worsen or fail to improve within two weeks.

Symptoms of mast cell stabilizer overdose

There is generally a very low risk of overdose with this type of medication. Symptoms of mast cell stabilizer overdose can be similar to the medication’s side effects, but are usually more intense. An overdose is unlikely to require additional medical treatment and is usually treated by discontinuing or reducing the amount of medication used. People who experience intense side effects with this type of medication should immediately contact their physician.

Pregnancy use issues

Mast cell stabilizers have not been tested in pregnant women. However, testing in animals suggests that large amounts of some injected mast cell stabilizers (cromolyn) can cause pregnancy complications as well as a decrease in the weight of the animal fetus. Pregnant women should not use mast cell stabilizers unless specifically instructed to by a physician aware of the pregnancy.

Using cromolyn in an eyedrop or inhaled form is unlikely to cause any interference with pregnancy. Animal and human studies with the mast cell stabilizers nedocromil and lodoxamide have not shown an increased risk of birth defects.

It is not currently known if mast cell stabilizers pass into breast milk. No problems with nursing babies have thus far been reported. However, most types of medications pass into breast milk in very small amounts, and breastfeeding mothers should contact their physician before using a mast cell stabilizer.

Child use issues with mast cell stabilizers

Most mast cell stabilizers have been safely tested in children. If the recommended dosage is used, this medication should not cause side effects different than those that appear in adults. Some types of mast cell stabilizer and their safe age of use include:

  • Lodoxamide (used to treat eye symptoms) has been safely tested in children as young as 2.

  • Cromolyn (inhalation) solution has been safely tested in children as young as 2, and the cromolyn inhalation aerosol has been tested in children as young as 5.

  • Cromolyn (nasal spray) has been safely tested in children as young as 2.

  • Cromolyn (oral) has not been thoroughly tested in young children, though it is frequently used in children as young as 2, and can be used to treat children younger than 2 in severe cases.

Depending on the judgment of the physician, mast cell stabilizers can be prescribed to children younger than the ages indicated. This class of drugs is often more suited to use in young patients because of the mild and relatively low number of side effects associated with their use.

Elderly use issues with mast cell stabilizers

There is currently no clinical data examining the use of mast cell stabilizers in the elderly. However, most experts do not expect this type of medicine to cause different side effects in elderly patients when used as directed by a physician. Some elderly individuals may experience side effects that are slightly more intense.

Mast cell stabilizers are often more suited to elderly patients because of the mild and relatively low number of side effects associated with their use.

Questions for your doctor

Preparing questions in advance can help patients to have more meaningful discussions with their physicians. Patients may wish to ask their doctors the following questions about mast cell stabilizers:

  1. Are mast cell stabilizers safe for me to take?

  2. How and when should I take this drug?

  3. How long will I have to take this drug?

  4. How long will it take for the drug to begin working?

  5. How will I know if the drug is working?

  6. What should I do if I miss a dose?

  7. Can I take more of the drug if my symptoms persist?

  8. What side effects may I develop?

  9. For what side effects should I seek medical attention?

  10. Are there medications, nutritional supplements or herbal medications I should avoid while taking this drug?

  11. What are other possible treatments if the drug does not relieve my symptoms?

  12. What should I do if I become pregnant while taking the drug?
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