Nacrom2%

Sodium cromoglicate 2% eye drops are used for the prevention and symptomatic treatment of:

• Acute, seasonal, and perennial allergic conjunctivitis (hay fever eyes and year-round eye allergies)
• Vernal keratoconjunctivitis, a more severe, chronic allergic eye condition, in some regulatory approvals

Sodium cromoglicate works best when used regularly and, where possible, started before allergen exposure begins (such as before the pollen season), since it prevents the allergic reaction rather than reversing it once symptoms have already started.

Contains sodium cromoglicate 2% w/v as the active ingredient in a sterile ophthalmic solution, commonly preserved with benzalkonium chloride.

Sodium cromoglicate eye drops are a mast cell stabilizer used to prevent and relieve the itching, redness, and watering of allergic conjunctivitis. Unlike antihistamine eye drops, which block histamine after it has already been released, sodium cromoglicate works by preventing the release of histamine and other allergy-triggering substances from mast cells in the first place - which is why it is most effective when used regularly and consistently, ideally starting before the allergy season or allergen exposure begins, rather than only when symptoms have already appeared.

Therapeutic Class: Ophthalmic Mast Cell Stabilizer (Antiallergic)

Sodium cromoglicate is poorly absorbed both from the eye and from the gastrointestinal tract, meaning systemic exposure and side effects are minimal with normal ophthalmic use. It works locally at the site of application, stabilizing mast cells in the conjunctiva so that a smaller proportion release their allergy-triggering contents when exposed to an allergen.

• Wash hands before use
• Tilt the head back, gently pull down the lower eyelid to form a pocket, and instill the prescribed number of drops into each eye
• Avoid touching the dropper tip to the eye or any surface, to prevent contamination
• Remove soft contact lenses before instillation and wait at least 15 minutes before reinserting them, given the benzalkonium chloride preservative, which can discolour or be absorbed by soft contact lenses
• Use at regular intervals throughout the day as prescribed - the therapeutic effect depends on consistent, regular use rather than only using it when symptoms flare
• Discard any remaining solution 4 weeks after first opening the bottle

No clinically significant drug interactions are established for sodium cromoglicate eye drops, given its minimal systemic absorption from ophthalmic use and lack of known interaction studies showing a clinically relevant effect.

Common side effects

• Transient stinging or burning sensation on instillation
• Temporary blurred vision immediately after application

Less common side effects

• Mild eye irritation
• Rarely, other local irritation symptoms

Serious effects (seek medical attention)

• Signs of a severe allergic reaction to the drops themselves: rash, swelling, difficulty breathing (rare)

Pregnancy

Cumulative clinical experience with sodium cromoglicate suggests no adverse effects on fetal development; as with all medicines, some caution should be exercised, particularly during the first trimester, and it should be used in pregnancy only where there is a clear need.

Breastfeeding

It is not known whether sodium cromoglicate is excreted in human breast milk, but based on its poor absorption, this is considered unlikely; there is no specific information suggesting any adverse effect on a breastfeeding infant.

• Regular, consistent use is essential for effectiveness, since sodium cromoglicate prevents allergic reactions rather than reversing existing ones; missing doses or using it only when symptoms flare reduces its effectiveness.
• May cause temporary blurred vision immediately after use; do not drive or operate machinery until normal vision is restored.
• Remove soft contact lenses before use, given the benzalkonium chloride preservative.
• Seek advice before discontinuing treatment, particularly if used for an ongoing chronic allergic condition, to plan an appropriate approach.
• Sodium cromoglicate is generally not recommended for use in children under 2 years, and its use in this age group should be discussed with a doctor.

Topical ophthalmic overdose is unlikely given minimal systemic absorption, though excessive use may increase local irritation. If the product is accidentally swallowed, contact a doctor or pharmacist for advice; significant systemic toxicity is not expected given the drug's poor gastrointestinal absorption.

Store at room temperature, away from direct sunlight and moisture, as directed on the product label. Discard the bottle 4 weeks after first opening, even if some solution remains.

• Children: Generally used in children over 4 years of age; some regulatory guidance restricts self-directed (over-the-counter) use to children over 6 years, with use in younger children conducted under the supervision of a pediatrician or ophthalmologist. Use in children under 2 years is generally not recommended.
• Elderly: No evidence suggests dosage alteration is required for elderly patients.

Sodium cromoglicate can be used long-term for chronic allergic eye conditions, or seasonally for hay-fever-related conjunctivitis, ideally starting before the expected allergy season and continuing regularly throughout the period of allergen exposure. Seek medical advice before stopping treatment if used on an ongoing basis.

Drug Class: Mast cell stabilizer (chromone)

Sodium cromoglicate inhibits the degranulation of sensitised mast cells that occurs when an allergen (such as pollen) binds to IgE antibodies on the mast cell surface. By stabilizing the mast cell membrane, it prevents or reduces the release of histamine and other inflammatory mediators responsible for the itching, redness, and watering of allergic conjunctivitis, and also inhibits certain later-phase (Type III, delayed) allergic reactions. It does not block the binding of IgE to mast cells or the interaction between IgE and allergen itself - its effect is specifically on preventing the resulting release of allergic mediators.

Sodium cromoglicate 2% eye drops are generally used in children over 4 years of age, following the same dosing as adults (1-2 drops, 4-6 times daily). It is considered a standard, well-tolerated option for pediatric allergic conjunctivitis, though self-directed use is often restricted to children over 6 years, with younger children managed under a doctor's guidance.