Cromolyn Sodium
Cromolyn sodium
Also known as: Crolom · Sodium cromoglycate
Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Dosing by species
🌎 NA — North America🌍 EU — Europe
Dogs
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Relief of seasonal allergy / Allergic conjunctivitis | one drop 2-6 times daily | topical ophthalmic | q4-12h | — | 🌎 NA |
Cats
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Relief of seasonal allergy / Allergic conjunctivitis | one drop 2-6 times daily | topical ophthalmic | q4-12h | — | 🌎 NA |
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Cromolyn sodium is a mast cell stabilizing agent used primarily in veterinary ophthalmology for the management of allergic conjunctivitis.
- It lacks intrinsic vasoconstrictor, antihistaminic, cyclooxygenase (COX) inhibition, or other direct anti-inflammatory properties.
- Because it prevents the release of inflammatory mediators rather than blocking their effects at the receptor level, it is most effective when used prophylactically or consistently over time.
Clinical Pearl: Mast cell stabilizers are generally very safe for long-term use in companion animals suffering from seasonal allergic conjunctivitis, though they may require frequent daily dosing to maintain efficacy.
Mechanism of action
Cromolyn sodium acts as a mast cell stabilizer. Upon antigen recognition, it blocks the degranulation of sensitized mast cells → prevents the release of histamine and slow-reacting substance of anaphylaxis (SRS-A) into the surrounding ocular tissues.
Safety & warnings
Adverse effects
- Stinging sensation upon application (low percentage of patients)
Precautions
May cause a mild, transient stinging sensation upon application. Ensure the dropper tip does not touch the eye or surrounding structures to prevent contamination.
Monitoring
- Resolution of clinical signs of allergic conjunctivitis (e.g., reduced hyperemia, chemosis, and pruritus)
Pharmacokinetics
Absorption
Minimal systemic absorption following topical ophthalmic application.
Overdose
Overdose via the topical ophthalmic route is highly unlikely to cause systemic toxicity. Excess drops will simply wash out of the conjunctival sac.
Available products
Formulations
- 4% Ophthalmic Solution
Human-labeled
- Cromolyn Sodium 4% Solution: 2.5, & 10 mL; Crolom® (Bausch & Lomb)
Regulatory status
No regulatory data for: 🇺🇸 US · 🇪🇺 EU · 🇬🇧 UK · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Store at room temperature away from moisture and direct sunlight. Keep the bottle tightly closed when not in use.
Client information
Administration Guide
- Wash hands before and after applying the medication.
- Apply the exact number of drops prescribed. Wait at least 5 minutes before applying any other eye medications.
- Do not touch the dropper tip to your pet's eye, eyelids, or any other surface to keep the medication sterile.
- Your pet may experience a brief, mild stinging sensation immediately after the drops are applied. If your pet rubs their eye excessively or the eye becomes more red, contact your veterinarian.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.