cromolyn sodium
Brand: Intal (inhaled — discontinued US market), NasalCrom (nasal), Gastrocrom (oral)
Prototype Drug
Drug Class: mast cell stabilizer
Drug Family: mast cell stabilizer
Subclass: chromone anti-inflammatory agent
Organ Systems: respiratoryimmunology
Mechanism of Action
Stabilizes mast cell membranes by inhibiting calcium influx through chloride channels, preventing degranulation and the release of mediators (histamine, leukotrienes, prostaglandins) in response to allergen exposure; mechanism is purely preventive — has no bronchodilatory or anti-inflammatory effect after mast cell degranulation has occurred.
mast cell chloride channelscalcium influx in mast cells
Indications
- prophylaxis of allergic asthma (particularly exercise-induced and allergen-triggered)
- prophylaxis of allergic rhinitis (nasal spray)
- mastocytosis and food allergy-associated GI symptoms (oral capsules)
Contraindications
- acute bronchospasm (not a bronchodilator)
- status asthmaticus
- hypersensitivity
Adverse Effects
Common
- bronchospasm (from inhaled powder — requires pre-medication with bronchodilator)
- cough
- throat irritation
- sneezing (nasal)
- nausea (oral)
Serious
- rare anaphylaxis
- pulmonary infiltrates with eosinophilia (rare)
Pharmacokinetics (ADME)
| Absorption | inhaled: approximately 8% systemic absorption; nasal: minimal; oral: <1% absorbed |
| Distribution | confined to airway mucosa and local tissue |
| Metabolism | not metabolized; excreted unchanged |
| Excretion | equal renal and biliary excretion of absorbed drug; unabsorbed oral drug excreted in feces |
| Half-life | approximately 80-90 minutes |
| Onset | preventive effect requires consistent use for 2-4 weeks; no acute effect |
| Peak | 15 minutes post-inhalation |
| Duration | requires 3-4 times daily dosing for prevention |
| Protein Binding | minimal |
| Vd | small (confined to airway) |
Drug Interactions
| Drug / Agent | Mechanism | Severity |
|---|---|---|
| no significant drug interactions | not metabolized; not a CYP substrate; very limited systemic absorption | minor |
Nursing Considerations
- Cromolyn is strictly preventive — it has no role in treating acute bronchospasm; patients must understand that it will not provide immediate relief and should continue using their rescue SABA for acute symptoms.
- Effective prophylaxis requires consistent dosing 3-4 times daily for both asthma and rhinitis; full preventive benefit may not be apparent for 2-4 weeks of regular use.
- For exercise-induced asthma prophylaxis, instruct patient to inhale cromolyn 10-15 minutes before exercise; this pre-exercise dosing must be timed correctly to achieve adequate mast cell stabilization at the time of exercise.
- The inhaled powder formulation can paradoxically cause bronchospasm in some patients; pretreatment with a SABA 15 minutes before cromolyn inhalation may prevent this effect.
Clinical Pearls
- Cromolyn sodium was a mainstay of asthma prevention therapy in the 1970s-1990s before ICS became dominant; it is now rarely used in asthma management because ICS are superior in efficacy and require less frequent dosing, but cromolyn remains useful in specific contexts (exercise-induced asthma, pediatric preference, pregnancy).
- Oral cromolyn sodium (Gastrocrom) for mastocytosis and food allergy-associated GI symptoms is unique — the drug is virtually unabsorbed when taken orally, acting entirely within the GI lumen to stabilize mucosal mast cells without any systemic effect.
Safety Profile
Pregnancy safe
Lactation use-with-caution
Renal Adjustment Not required
Hepatic Adjustment Not required
TDM Not required
Concordance Terms
Cross-referenced clinical concepts — click any term to see all content where it appears.