Cromolyn Sodium | Mechanism of action, Uses & Side effects

What is Cromolyn sodium?

Cromolyn Sodium – the sodium salt of Cromolyn is used to treat the rare condition- Mastocytosis. It is a condition that is caused by too many mast cells in a body. It has a molecular formula of C23H14Na2O11 and is also known as Sodium cromoglycate, Disodium cromoglycate, and sodium cromoglicate. Gastrocrom is the common brand name of Cromolyn sodium. 

In this article, you will get to know everything about cromolyn sodium.


Chemical Structure of Cromolyn Sodium

Name of Product Cromolyn Sodium
IUPAC Name disodium;5-[3-(2-carboxylato-4-oxochromen-5-yl)oxy-2-hydroxypropoxy]-4-oxochromene-2-carboxylate
Synonyms CROMOLYN SODIUM, Sodium cromoglycate, Disodium cromoglycate, Intal, Aarane
CAS No 15826-37-6
Molecular Formula C23H14Na2O11
Molecular Weight 512.3 g/mol
Pubchem CID 27503
Pubchem SID 463577010


Mechanism of action

Cromolyn sodium inhibits the release of inflammatory mediators like histamine and leukotrienes from the sensitized mast cells causing allergies. It basically works at the surface blocking the degranulation that further expands the allergies. It is different from antihistamine medications in reducing the action of histamines released from the mast cells. Cromolyn sodium hinders immediate and late reactions. Its use has been mainly related to flushing, headaches, vomiting, nausea, etc.

Cromolyn Sodium-Mechanism of action


Pharmacokinetics refers to the movement and modification of the drug inside the body which comprises of 4 major phases-absorption, distribution, metabolism & excretion. The key components related to Cromolyn Sodium’s pharmacokinetics are-

  • Oral administration of this medication results in poor absorption of the medicine, and the onset of its effects might take two to six weeks. Similarly, less than 0.07% of administered cromolyn sodium is absorbed from ophthalmic solution or drops.
  • Cromolyn sodium has a half-life of approximately 80 to 90 minutes and a bioavailability ranging from 0.5 to 2%.
  • The effect it has on mast cells can be expected to remain for around 6 hours after administration
  • The vast majority of the medicine, which is around 98%, is eliminated unchanged through the feces.


Cromolyn sodium is a medication that prevents the release of substances that cause inflammation and swelling in the nasal airways. It is thus used to manage bronchial asthma, allergic rhinitis, and certain allergic eye conditions such as vernal conjunctivitis, keratitis, and keratoconjunctivitis. It prevents and treats stuffy and runny nose, sneezing, and other allergy symptoms. It is also used to treat allergic dermatitis, which can cause eczema on the skin.

It is also used for the treatment of Mastocytosis that usually occurs with the accumulation of too many mast cells. The major release of the mast cells causes the skin and gut problems. Cromolyn stabilizes the mast cells.

Additionally, a study is also being going on in the US regarding the use of Cromolyn sodium for treatment of COVID-19 pneumonia. The study is based on the hypothesis that cromolyn, when combined with standard COVID-19 treatment, will improve patient symptoms and lead to faster recovery with improved quality of life.

Uses of Cromolyn Sodium

Available preparations

  • In a nebulizer solution that can be administered as an aerosol to patients suffering from asthma.
  • As a nasal spray for the treatment of allergic rhinitis (Rynacrom in the UK, Lomusol in France, Nasalcrom (the only over-the-counter form in the US), and Prevalin (a non-direct version in the Netherlands)).
  • As ophthalmic preparations/eye drops (Opticrom and Optrex Allergy in the United Kingdom; Crolom and Cromolyn in Canada) for the treatment of allergic conjunctivitis.
  • In an oral form (Gastrocrom, Nalcrom) to treat mastocytosis, mast cell activation syndrome, dermatographic urticaria and ulcerative colitis. In the treatment of food allergies, another oral medication called Intercron (sodium cromoglicate in distilled water, manufactured in France by Zambon) is utilised.
  • As an inhaler for preventive management of asthma.

How to use Cromolyn sodium

Cromolyn comes in the solution form with a special nasal applicator. According to the symptoms, it is usually inhaled 3-6 times. It works best if used before you come in contact with an allergic substance. For seasonal allergies, it is advised to take regularly till the season changes. 

The exact dosage can only be told by the doctor or the pharmacist. 4 weeks is the minimum time for cromolyn to work; later if the condition does not improve, then contact your doctor. 

In case of ampoules, swallowing an ampoule is not recommended, the content it contains is used in making a solution. Break the ampoule and squeeze in the glass of water, stir it well and drink it right away.


Oral Solution – For Mastocytosis- In adults, 200 mg PO (by mouth) four times daily and 100 mg PO (by mouth) four times daily in children.

Nasal spray – 5.2 mg/1 actuation

Ophthalmic solution – 4% (10mL)

Inhalation solution – 10mg/1mL


Some necessary precautions must be taken. Precaution is always better than cure. Caution is necessary to be followed in the patients with a history of liver, kidney disease, pregnancy, or any other allergies record.

Some extra warnings include: 

  • Consult a doctor if you are allergic to cromolyn.
  • Consult a doctor whether it is safe to take vitamins along with it or not.
  • Consult a doctor if you have kidney or liver disease.
  • Consult a doctor if you are pregnant or you are breast-feeding.

Side effects

There are some additional or unwanted effects that you might face with the medicine. It is not necessary that it will happen with everyone, but if in case any of these effects are visible and are bothering you, then you must seek medical assistance. 

Common side effects associated with the use of Cromolyn Sodium are –

  • Rash, itching, hives
  • Headache, feeling irritable
  • Nausea, diarrhea, stomach pain
  • Muscle pain

Some serious side effects include-

  • White patches or sores inside your mouth or on your lips
  • Swelling of your tongue
  • Trouble swallowing
  • Tightness in the chest


Q. Can cromolyn sodium be a substitute for a prednisone?

Cromolyn sodium cannot be used as a substitute for prednisone

Q. Does cromolyn sodium cause weight gain?

It is not a necessary side effect noted. However, during the treatment, some weight loss might be observed and you may gain back what you have lost. This is the reason why a possible weight gain might be observed. 

Q. Is cromolyn sodium an antihistamine?

Cromolyn sodium differs from antihistamine which works by reducing the action of histamine. 

Q. Is cromolyn sodium a steroid?

It is not a steroid, as steroids inhibit late response whereas cromolyn sodium inhibits the immediate and late reaction in case of allergies.

Q. What is the minimum time for cromolyn sodium to work?

Oral administration of this medication results in poor absorption of the medicine, and the onset of its effects might take from two to six weeks.

Q. Is cromolyn sodium addictive?

Cromolyn Sodium preparations are non-addictive, people can use them easily for 12 weeks daily. 

Q. Is there any difference between cromolyn and other anti-asthma medications?

It is the only anti-asthmatic that blocks both early and late asthmatic responses in response to allergen inhalation and exercise, so it is used to treat mild to moderate bronchial asthma.

Q. Is cromolyn sodium an over-the-counter drug?

 Cromolyn sodium is only available on the doctor’s prescription and not an over-the-counter drug.


The information provided here is based on general knowledge, articles, research publications etc. and we do not claim the authenticity of any of the information provided above. We do not claim or suggest/advise any medical, therapeutic, health or nutritional benefits of Cromolyn sodium. We do not supply or promote our Cromolyn sodium product for the applications which are covered by valid patents and which are not approved by the FDA.

Macsen Labs is a manufacturer and supplier of high-quality Cromolyn sodium.

Buy Cromolyn sodium from Macsen Labs