What is the dosage of oral Cromolyn (Cromolyn Sodium) for Mast Cell Activation Syndrome (MCAS)?

Oral Cromolyn Sodium Dosage for Mast Cell Activation Syndrome (MCAS)

The standard dosage of oral cromolyn sodium for MCAS is 200 mg four times daily (taken 30 minutes before meals and at bedtime) for adults and adolescents 13 years and older. 1

Dosing Details

Initial Dosing

• Adults and adolescents (≥13 years): Two ampules (200 mg) four times daily, taken 30 minutes before meals and at bedtime 1
• Children (2-12 years): One ampule (100 mg) four times daily, taken 30 minutes before meals and at bedtime 1
• Children under 2 years: Not recommended 1

Titration and Maintenance

• If symptoms are not adequately controlled within 2-3 weeks, the dose may be increased but should not exceed 40 mg/kg/day 1
• Once therapeutic response is achieved, the dose may be reduced to the minimum required to maintain symptom control 1
• Regular administration is essential for effectiveness 1

Administration Instructions

1. Break open ampule(s) and squeeze contents into a glass of water
2. Stir solution thoroughly
3. Drink all of the liquid
4. Take at least 30 minutes before meals and at bedtime 1

Efficacy Considerations

Oral cromolyn sodium primarily targets gastrointestinal symptoms in MCAS. The 2019 AAAAI Mast Cell Disorders Committee Work Group report indicates that:

• Oral cromolyn is used predominantly for gastrointestinal symptoms, though its mechanism of action is not fully understood 2
• It may also reduce pruritus when taken orally or applied topically 2
• Patients should be counseled that onset of action can be delayed and should take it for at least 1 month before determining effectiveness 2

Important Clinical Considerations

• Cromolyn sodium has no significant adverse effects, making it a safe option for long-term use 2
• Cromolyn works by inhibiting the release of mediators from mast cells 3
• Cromolyn sodium is poorly absorbed after oral administration, which limits its systemic effects 4
• For some patients, doses may need to be increased during periods of increased sensitivity or during menstrual cycles 5

Treatment Algorithm for MCAS

1. First-line therapy: H1 and H2 antihistamines (often at higher than standard doses) 2
2. Add-on therapy: Oral cromolyn sodium at 200 mg four times daily 2, 1
3. Inadequate response: Consider increasing cromolyn dose (not exceeding 40 mg/kg/day) 1
4. Persistent symptoms: Consider additional therapies such as leukotriene modifiers or omalizumab 2

Limitations and Alternatives

• Some studies suggest that flavonoids like quercetin and luteolin may be more potent than cromolyn in inhibiting mast cell mediator release 4, 6
• In some cases, inhaled cromolyn sodium may provide additional benefit for symptoms not controlled by oral administration, such as bone pain, fatigue, and headache 5
• For patients with severe symptoms, systemic steroids may be considered for short-term use 2

Remember that while cromolyn sodium is generally well-tolerated, its effectiveness varies among patients, and it may take several weeks to achieve optimal symptom control.