Sodium Cromoglicate 2%

How it works

It stabilises sensitised conjunctival mast cells and inhibits their degranulation, reducing the release of histamine and other inflammatory mediators that cause itching, redness and watering.

Prescribing in practice

• It works prophylactically and takes regular continued use over several days to reach full effect, so it is unsuitable as a single-dose treatment for an acute flare and should be used consistently throughout the allergy season.
• It treats allergy, not infection, so a painful red eye with discharge or reduced vision needs reassessment.
• Preserved formulations are incompatible with soft contact lens wear during instillation, though preservative-free options exist.

Monitoring

No laboratory monitoring is required; review symptom control and adherence to regular dosing.

Counselling the patient

• Use the drops regularly every day, ideally starting before the season, rather than only when symptoms appear.
• Allow several days of continuous use before judging how well it works.
• Remove soft contact lenses before instilling preserved drops.

Evidence & guidelines

Sodium cromoglicate is a long-established, well-tolerated prophylactic treatment for allergic conjunctivitis, available over the counter and supported by the SPC and allergy guidance.