Mast Cell Stabiliser — Allergic Conjunctivitis Pregnancy: Considered safe — negligible systemic absorption; widely used during pregnancy for allergic disease; consult specialist for formal advice

Sodium Cromoglicate 2%

Brand names: Opticrom, Catacrom, Hay-Crom

Adult dose

Dose: 1–2 drops four times daily

Route: Topical ophthalmic

Frequency: Four times daily (may be increased to six times daily in severe symptoms)

Max: 6 times daily

Start treatment before allergen season begins for maximum benefit; may take 2–4 days to achieve full effect; available OTC; contact lenses should be removed before instillation

Paediatric dose

Route: Topical

Frequency: Four times daily

Max: 2 drops six times daily

Licensed from 1 year of age; widely used in paediatric allergic conjunctivitis — safe long-term profile

Dose adjustments

Renal

No adjustment required (negligible systemic absorption)

Hepatic

No adjustment required

Clinical pearls

Mechanism: inhibits degranulation of sensitised mast cells — prevents release of histamine, prostaglandins, and leukotrienes; mechanism not fully characterised but involves blocking chloride channels preventing calcium entry required for mast cell degranulation
Prophylactic vs symptomatic: cromoglicate is primarily prophylactic — start 4–6 weeks before allergen season; unlike antihistamines (e.g. olopatadine), cromoglicate provides no immediate antihistamine effect; for acute symptom relief, combine with or switch to a dual-acting antihistamine/mast-cell stabiliser
BNF first-line for seasonal allergic conjunctivitis in children: well-established safety profile; available over-the-counter; appropriate for long-term prevention during pollen season; SIGN and NICE guideline-recommended mast cell stabiliser
Nedocromil vs cromoglicate: nedocromil 2% eye drops (Rapitil) have similar mechanism but additional anti-inflammatory properties targeting eosinophils — may be more effective for perennial allergic conjunctivitis; both available in UK
Preserved formulation: most cromoglicate preparations contain benzalkonium chloride — remove contact lenses before instillation and wait 15 minutes before reinsertion; the preservative can damage contact lens polymers and irritate sensitised ocular surfaces

Contraindications

Hypersensitivity to sodium cromoglicate or benzalkonium chloride (preservative)

Side effects

Transient stinging or burning on instillation
Blurred vision (transient)
Eye irritation
Rarely — rash or urticaria

Interactions

Minimal drug interactions — negligible systemic absorption; contact lens incompatibility with benzalkonium chloride (remove before instilling)

Monitoring

Symptom control (itching, redness, discharge)
Compliance with prophylactic regimen
Contact lens wear patterns

Reference: BNFc; BNF 90; NICE CKS (Allergic Conjunctivitis 2022); SPC Opticrom; SIGN 141 (Allergic Rhinitis). Verify against your local formulary and the latest BNF before prescribing.

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways