cromolyn sodium
Gastrocrom, Intal, Intal Inhaler, Intal Nebulizer Solution, Nasalcrom, Opticrom

Available forms
Available by prescription only
Aerosol: 800 mcg/metered spray
Ophthalmic solution: 4%
Oral concentrate: 100 mg/5 ml
Solution: 20 mg/2 ml for nebulization
Nasal solution: 5.2 mg/metered spray (40 mg/ml)

Indications and dosages
 Adjunct in treatment of severe perennial bronchial asthma. Adults and children older than age 5: Two inhalations q.i.d. at regular intervals; aqueous solution administered through a nebulizer, one ampule q.i.d.
 Prevention and treatment of allergic rhinitis. Adults and children age 2 and older: One spray (5.2 mg) of nasal solution in each nostril t.i.d. or q.i.d.
 Prevention of exercise-induced bronchospasm. Adults and children older than age 5: Two metered sprays using inhaler no more than 1 hour before anticipated exercise.
 Inhalation of 20 mg of oral inhalation solution may be used in adults or children age 2 and older. Repeat inhalation as required for protection during long exercise.
 Allergic ocular disorders (giant papillary conjunctivitis, vernal keratoconjunctivitis, vernal keratitis, allergic keratoconjunctivitis). Adults and children older than age 4: Instill one to two drops in each eye four to six times daily at regular intervals. One drop contains about 1.6 mg cromolyn sodium.
 Systemic mastocytosis. Adults: 200 mg P.O. q.i.d.
Children ages 2 to 12: 100 mg P.O. q.i.d.
Children younger than age 2: 20 mg/kg daily P.O. divided in four equal doses.
 Food allergy, inflammatory bowel disease ◇. Adults: 200 mg P.O. q.i.d. 15 to 20 minutes before meals.

Pharmacodynamics
Antasthmatic action: Cromolyn prevents release of mediators of type I allergic reactions, including histamine and slow-reacting substance of anaphylaxis (SRS-A), from sensitized mast cells after the antigen-antibody union has taken place. Cromolyn doesn’t inhibit binding of IgE to mast cells nor the interaction between cell-bound IgE and the specific antigen. It does inhibit the release of substances (such as histamine and SRS-A) in response to IgE binding to mast cells. Main site of action occurs locally on the lung mucosa, nasal mucosa, and eyes.
Bronchodilating action: Besides mast cell stabilization, recent evidence suggests that drug may have a bronchodilating effect by an unknown mechanism. Comparative studies have shown cromolyn and theophylline to be equally efficacious but less effective than orally inhaled beta₂-adrenergic agonists in preventing bronchospasm.
Ocular antiallergy action: Cromolyn inhibits degranulation of sensitized mast cells that occurs after exposure to specific antigens, preventing release of histamine and SRS-A.
 Cromolyn has no direct anti-inflammatory, vasoconstrictor, antihistamine, antiserotonin, or corticosteroid-like properties.
 Cromolyn dissolved in water and given orally has been found to be effective in managing food allergy, inflammatory bowel disease (Crohn’s disease, ulcerative colitis), and systemic mastocytosis.

Pharmacokinetics
Absorption: Only 0.5% to 2% of an oral dose is absorbed. The amount reaching the lungs depends on patient’s ability to use inhaler correctly, amount of bronchoconstriction, and size or presence of mucus plugs. The degree of absorption depends on method of administration; most absorption occurs with the aerosol via metered-dose inhaler, and least occurs with the administration of the solution via power-operated nebulizer. Less than 7% of an intranasal dose of cromolyn as a solution is absorbed systemically. Only minimal absorption (0.03%) of an ophthalmic dose occurs after instillation into the eye. Absorption half-life from the lung is 1 hour. A plasma level of 9 ng/ml can be achieved 15 minutes after a 20-mg dose.
Distribution: Cromolyn doesn’t cross most biological membranes because it’s ionized and lipid-insoluble at the body’s pH. Less than 0.1% of a dose crosses the placental barrier; it isn’t known if drug appears in breast milk.
Metabolism: None significant.
Excretion: Excreted unchanged in urine (50%) and bile (about 50%). Small amounts may be excreted in the feces or exhaled. Elimination half-life is 81 minutes.

Contraindications and precautions
Contraindicated in patients experiencing acute asthma attacks or status asthmaticus and in patients hypersensitive to drug. Use inhalation form cautiously in patients with cardiac disease or arrhythmias.

Interactions
None reported.

Adverse reactions
CNS: dizziness, headache.
EENT: irritated throat and trachea, nasal congestion, pharyngeal irritation, sneezing, nasal burning and irritation, epistaxis, lacrimation, swollen parotid gland.
GI: nausea, esophagitis, abdominal pain, bad taste.
GU: dysuria, urinary frequency.
Musculoskeletal: joint swelling and pain.
Respiratory: bronchospasm (after inhalation of dry powder), cough, wheezing, eosinophilic pneumonia.
Skin: rash, urticaria.
Other: angioedema.

Effects on lab test results
None reported.

Overdose and treatment
No information available.

Special considerations
• Therapeutic effects may not occur for 2 to 4 weeks after therapy starts.
• Bronchospasm or cough occasionally occurs after inhalation and may require stopping therapy. Prior bronchodilation may help but it may still be necessary to stop the cromolyn therapy.
• Asthma symptoms may recur if cromolyn dosage is reduced below the recommended dosage.
• Use reduced dosage in patients with impaired renal or hepatic function.
• Eosinophilic pneumonia or pulmonary infiltrates with eosinophilia requires stopping drug.
• Nasal solution may cause nasal stinging or sneezing immediately after instillation of drug, but this reaction rarely requires discontinuation of drug.
• Protect oral solution and ophthalmic solution from direct sunlight.
• Monitor pulmonary status before and immediately after therapy.
• Pulmonary function tests are needed to confirm significant bronchodilator-reversible component of airway obstruction in patients considered for cromolyn therapy.
• Watch for recurrence of asthmatic symptoms when corticosteroids are also used. Use only when acute episode has been controlled, airway is cleared, and patient is able to inhale.
Pregnant patients
• Adverse fetal effects occur when cromolyn sodium is administered parenterally in high doses with high-dose isoproterenol.
Pediatric patients
• The safety and efficacy of the aerosol for oral inhalation in children younger than age 5 haven’t been established. The safety of the nebulizer solution in children younger than age 2 hasn’t been established. Safety of nasal solution in children younger than age 2 hasn’t been established.

Patient education
• Teach correct use of metered-dose inhaler: Exhale completely before placing mouthpiece between lips; then inhale deeply and slowly with steady, even breath. Remove inhaler from mouth, hold breath for 5 to 10 seconds, and exhale.
• Urge patient to call if drug causes wheezing or coughing.
• Instruct patient with asthma or seasonal or perennial allergic rhinitis to administer drug at regular intervals to ensure clinical effectiveness.
• Advise patient that gargling and rinsing mouth after administration can help reduce mouth dryness.
• Tell patient taking prescribed adrenocorticoids to continue taking them during therapy, if appropriate.
• Instruct patient who uses a bronchodilator inhaler to administer dose about 5 minutes before taking cromolyn (unless otherwise indicated); explain that this step helps reduce adverse reactions.

Reactions may be common, uncommon, life-threatening, or COMMON AND LIFE THREATENING.
◆ Canada only
◇ Unlabeled clinical use