FDA-filed SPL labeling · retrieved through openFDA

Cromolyn Ophthalmic

Cromolyn ophthalmic is an eye drop used to treat vernal keratoconjunctivitis, vernal conjunctivitis, and vernal keratitis — seasonal allergic eye conditions that cause itching, tearing, and eye discomfort.

Brand names CrolomNasalcromGastrocrom
Drug classes Decreased Histamine Release
Rx Form 1 Route Ophthalmic
Dr. Brian Staiger, PharmD, BCPS
Reviewed by Last reviewed Jul 10, 2026
🧬 Where this information comes from Click to expand

The clinical label records used on this page are FDA-filed Structured Product Labeling (SPL) retrieved through openFDA. We identified 6 clinical label sets within the page’s selected clinical scope after exact ingredient or ingredient-combination matching and applicable route/form matching. Forms, routes, brands, labelers, strengths, and NDC product-record counts are built separately from matching FDA National Drug Code Directory records. The linked DailyMed document is a representative official source for verification, not the page’s only clinical source. View the linked label on DailyMed →

At a glance
Linked label effectiveJan 25, 2022
Clinical labels in scope 6
AvailabilityRx
Earliest approval/marketing year 1982
FDA-listed product records 14
Boxed warningNone found in compared labels
How we combine label and product data →
No current FDA shortage listed · checked Sep 23, 2026
Other forms & routes:
Cromolyn Ophthalmic at a glance The quick version — the full detail is in the Patient Information Guide below.
💊
HelloPharmacist Editorial Team Bottom Line
Cromolyn Sodium eye drops treat vernal keratoconjunctivitis, vernal conjunctivitis, and vernal keratitis by preventing allergic cells in the eye from releasing irritating chemicals. The drops need to be used on a regular schedule — not just as needed — and it may take a few days to several weeks before you get the full benefit. Stinging on instillation is common and usually harmless, but stop use and seek care right away if you have trouble breathing, swelling, or a rash.

📖 Cromolyn Ophthalmic: Patient Information Guide

A plain-language walkthrough of Cromolyn Ophthalmic — what it treats, how it works, how it’s taken, side effects, warnings and interactions. Tap any section to expand it.

🎯What it's used for

Cromolyn sodium ophthalmic solution is approved for allergic eye conditions that tend to recur seasonally. All three supported uses apply specifically to Cromolyn Sodium ophthalmic solution 4%:

  • Vernal keratoconjunctivitis — a recurring seasonal allergy affecting both the conjunctiva (eye's outer lining) and the cornea
  • Vernal conjunctivitis — seasonal allergic inflammation of the conjunctiva
  • Vernal keratitis — seasonal allergic inflammation of the cornea
⚙️How it works

Cromolyn sodium stabilizes mast cells — immune cells that sit in the tissues of your eye and release irritating chemicals when they encounter allergens. Normally, those cells release histamine and another substance called SRS-A (slow-reacting substance of anaphylaxis), which drive itching, tearing, and redness. Cromolyn sodium blocks the process that triggers that release, so those chemicals never get out in the first place. It has no direct antihistamine or anti-inflammatory effect on its own — it simply prevents the allergic cascade from starting.

💊How it's taken

Cromolyn Sodium eye drops are applied directly to the eye. The usual approach is 1 or 2 drops in each eye, four to six times daily, spaced out at regular intervals throughout the day. Consistent timing matters — the drops are most effective when used on a set schedule rather than only when symptoms flare.

  • Symptoms like itching and tearing often improve within a few days, but some people need up to six weeks of treatment for full benefit
  • Once improvement is established, continue using the drops for as long as your prescriber directs to keep symptoms under control
  • If you miss a dose, take it as soon as you remember and then return to your regular schedule — do not double up
🤒Side effects — in detail

The most common side effect is a brief stinging or burning sensation right after the drops go in — this is generally harmless and usually fades quickly. Other reported effects include:

  • Eye irritation or redness (conjunctival injection)
  • Watery or itchy eyes
  • Dryness around the eye
  • Puffy eyes
  • Styes (small eyelid bumps)

Rarely, serious allergic reactions have occurred, including trouble breathing, swelling, or a rash. If any of these happen, stop using the drops and get medical help right away.

⚠️Warnings & precautions
  • Serious allergic reactions are rare but possible — if you experience breathing difficulty, facial or eye swelling, or a rash after using the drops, seek emergency care immediately
  • Do not use Cromolyn Sodium eye drops if you are allergic to cromolyn sodium or to any ingredient in the solution
  • The drops require regular, consistent use to be effective — skipping doses or using them only occasionally will reduce how well they work
  • If a corticosteroid eye medication is also prescribed, your doctor will guide you on using both together safely
🔀What it interacts with

The FDA label for Cromolyn Sodium ophthalmic solution does not identify specific drug, food, or substance interactions to be aware of. Always tell your doctor and pharmacist about all eye drops and other medications you are using.

This is not a complete list of interactions. Always talk with your doctor or pharmacist before starting, stopping, or changing any medication.

📋Before taking it
  • Do not use these drops if you have a known allergy to cromolyn sodium or any component of the solution
  • Tell your doctor about all eye conditions and any other eye medications — prescription or over-the-counter — that you are currently using
  • Inform your prescriber if you are pregnant, planning to become pregnant, or breastfeeding so they can weigh the benefits and risks with you
📡Pharmacodynamics — effects in the body

Cromolyn sodium prevents sensitized mast cells in the eye from degranulating — meaning it stops them from releasing the chemical mediators (histamine and SRS-A) that cause the redness, itching, tearing, and discharge of allergic eye disease. It does not constrict blood vessels, block histamine receptors directly, or reduce existing inflammation on its own. Its benefit comes from preventing the allergic response from being triggered in the first place.

🔬Pharmacokinetics — how your body processes it

Cromolyn sodium is very poorly absorbed when applied to the eye. In animal studies, less than 0.07% of the administered dose reached the bloodstream, and in human volunteers, approximately 0.03% was absorbed following eye administration. Only trace amounts (less than 0.01%) penetrate into the aqueous humor (the fluid inside the eye), and those trace amounts clear from the eye within 24 hours after treatment stops.

📦How to store it

Store at 20° to 25°C (68° to 77°F) . Protect from light-store in original carton. Keep out of reach of children.

📄 Written from Cromolyn Ophthalmic’s FDA-approved label information, summarized in plain language with AI, and reviewed by our pharmacy team before publication. Every point is grounded in that labeling — nothing is invented. How we use AI →

🩺 Pharmacist Counseling Corner

Quick, plain-English answers to the questions patients ask most about Cromolyn Ophthalmic — the kind of thing our pharmacy team would talk through with you at the counter.

What exactly is this eye drop treating — is it just regular eye allergies?
It's actually for a specific group of recurring seasonal allergic eye conditions called vernal keratoconjunctivitis, vernal conjunctivitis, and vernal keratitis. 'Vernal' means they tend to come back seasonally, often in warmer months, and they can affect the outer lining of the eye and the cornea. If you're not sure whether your eye condition fits that category, your eye doctor can confirm.
How long before these drops actually start helping?
Most people start to notice less itching, tearing, redness, and discharge within a few days of using the drops consistently. That said, for some people it can take up to six weeks of regular use before the full benefit kicks in. The key word is 'regular' — the drops work best when you use them on a set schedule, not just when your eyes flare up.
My eyes sting when I put the drops in. Is that normal?
Yes, that brief stinging or burning right after instillation is actually the most commonly reported side effect with these drops. It typically fades quickly and isn't a sign that something is wrong. If the stinging is severe, persistent, or your symptoms get worse rather than better, let your doctor know.
Can I stop using them once my eyes feel better?
It's best to keep using them for as long as your prescriber directed, even after you feel improvement. Stopping too soon can allow symptoms to come back. Once the drops have helped bring your symptoms under control, continuing them helps keep that improvement going through the season.
Is there anything I should watch for that would mean I need to call for help right away?
Yes — although it's rare, some people have had a serious allergic reaction to these drops, including difficulty breathing, swelling, or a rash. If any of those happen after using the drops, stop using them immediately and seek medical attention right away. That kind of reaction is different from the mild stinging that's common with these drops.
Can I use these drops alongside other eye medications my doctor prescribed?
In some cases, yes — the label notes that corticosteroid eye medications can be used at the same time as Cromolyn Sodium drops if your doctor decides that's appropriate. Always make sure your prescriber and pharmacist know about every eye drop or medication you're using so they can advise on the safest way to use them together.
Is Cromolyn Ophthalmic available over the counter?
Cromolyn Ophthalmic is dispensed by prescription according to its FDA labeling, so it isn't sold over the counter. Your prescriber and pharmacist will determine if it's appropriate for you.
When was Cromolyn Ophthalmic first available?
Cromolyn Ophthalmic has been available in the United States since at least 1982, based on FDA approval history (Drugs@FDA) and product marketing records.
Who makes Cromolyn Ophthalmic?
Cromolyn Ophthalmic is supplied by 6 manufacturers listed in the FDA NDC Directory, including A-S Medication Solutions, Preferred Pharmaceuticals Inc., Proficient Rx LP.

💬 Answers drafted from Cromolyn Ophthalmic’s FDA-approved label information, summarized in plain language with AI, and reviewed by our pharmacy team before publication. Grounded in that labeling — nothing is made up. How we use AI →

🧰 Keep exploring

💊 How Cromolyn Ophthalmic comes

Cromolyn Ophthalmic is available in 1 form. Different forms and brands can have different approved uses, doses, schedules, and directions. Follow the instructions for your exact product, and do not switch forms without guidance from your prescriber or pharmacist.

Eye drops

In the eye
How this form is used
What it may be used for
  • Cromolyn Sodium ophthalmic solution is used to treat vernal keratoconjunctivitis
  • Cromolyn Sodium ophthalmic solution is used to treat vernal conjunctivitis
  • Cromolyn Sodium ophthalmic solution is used to treat vernal keratitis
Important instructions
  • Cromolyn Sodium eye drops are instilled as 1 or 2 drops in each eye, four to six times a day at regular intervals
  • Cromolyn Sodium eye drops must be used on a consistent schedule — regular timing is key to how well they work
  • Cromolyn Sodium eye drops may be used alongside corticosteroid eye treatments if your doctor prescribes them together
  • Continue using Cromolyn Sodium eye drops for as long as your doctor directs, even after symptoms improve
Available strengths 1 strength
14 FDA-listed product records

📊 Cromolyn Ophthalmic across the U.S. market

How Cromolyn Ophthalmic appears in the FDA’s National Drug Code Directory — including its dosage forms, strengths, brand names, manufacturers, and FDA-listed product records. These are directory records, not sales or prescription volume.

1
Dose forms
6
Manufacturers
1
Brand names
14
FDA-listed product records
1982
First marketed
A-S Medication Solutions36%
Preferred Pharmaceuticals Inc.14%
Proficient Rx LP14%
RPK Pharmaceuticals, Inc.14%
Sandoz Inc14%
Akorn7%

Share of FDA-listed product records by manufacturer — FDA National Drug Code Directory. Record counts are not sales or prescription volume.

📈 How widely Cromolyn Ophthalmic is used

A general measure of how commonly Cromolyn Ophthalmic is prescribed, based on Medicaid — one of the largest public drug programs. The figure below is prescriptions filled in Q1–Q4 2025, summed across every form and brand of the drug.

Think of this as a proxy for how widely Cromolyn Ophthalmic is used, drawn from freely available public data. Medicaid is just one program — these numbers don’t include Medicare, other government coverage, or commercial and cash-pay prescriptions, so real-world use is higher than what’s shown here.

71,026
Medicaid prescriptions filled (Q1–Q4 2025)
$1.5M gross Medicaid reimbursement (before mandatory rebates — net cost is lower)

How commonly is Cromolyn Ophthalmic prescribed? Of the 1,596 medications we measure, Cromolyn Ophthalmic ranks #560 by Medicaid prescriptions — more than 65% of them.

Where Cromolyn Ophthalmic ranks among the drugs we measure · Q1–Q4 2025 · neighbors ±5

Utilization by Cromolyn Ophthalmic product

Pick a product to see its own Medicaid numbers. Each chip is one clinical product — a specific strength & dosage form as defined by RxNorm — with brand-name and generic versions combined.

cromolyn sodium 40 MG/ML Ophthalmic Solution

71,026 Medicaid prescriptions (Q1–Q4 2025) 100% of Cromolyn Ophthalmic prescriptions shown $1.5M gross reimbursement (before rebates) ≈ $21 per prescription (gross)

Summed across the 1 of 9 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 831109

Shares are of the Medicaid prescriptions shown here. Product grouping follows RxNorm (the National Library of Medicine’s drug terminology), so “one product” means one strength & dosage form regardless of manufacturer. Dollar figures are gross Medicaid reimbursement before mandatory rebates — rebates (often large, especially for brand-name drugs) are confidential, so actual net cost to Medicaid is lower than shown.

Source: Medicaid State Drug Utilization Data (CMS), aggregated by generic ingredient — summed across every NDC (all brands, strengths, salt forms and dosage forms) of Cromolyn Ophthalmic, and across all states and both fee-for-service and managed-care claims. A general popularity signal; it excludes Medicare, commercial insurance and cash prescriptions, so it is not total U.S. use. Based on the 1 of 9 listed Cromolyn Ophthalmic NDCs with Medicaid activity.

🔍 Compare Cromolyn Ophthalmic products

A representative set of FDA-listed product records for Cromolyn Ophthalmic — across manufacturers, strengths, and dosage forms, grouped by form with each product’s manufacturer and how the FDA approved it. The same medicine may be made and packaged by different companies, so a single drug can have many directory entries. (It’s also why a refill can look different — a new shape, color, or box — even though it contains the same medication.)

Strength Route Manufacturer / Labeler Category Details
💊Eye drops
40 mg/mL Ophthalmic A-S Medication Solutions × 5 listings ANDA View NDC →
40 mg/mL Ophthalmic Akorn ANDA View NDC →
40 mg/mL Ophthalmic Preferred Pharmaceuticals Inc. × 2 listings ANDA View NDC →
40 mg/mL Ophthalmic Proficient Rx LP × 2 listings ANDA View NDC →
40 mg/mL Ophthalmic RPK Pharmaceuticals, Inc. × 2 listings ANDA View NDC →
40 mg/mL Ophthalmic Sandoz Inc × 2 listings ANDA View NDC →

Showing 14 of 14 products — FDA National Drug Code Directory. See every product, package size and price: browse all 14 Cromolyn Ophthalmic NDCs →

RxNorm Concept Web — From Ingredient to Every Form and Strength

This page starts with one ingredient concept (IN). The branches below show its dose-form concepts (SCDF), then the available clinical drug and strength concepts (SCD). Combination products remain separate concepts with their own pages.

Ingredient (IN) Cromolyn Ophthalmic RxCUI 42612 8 dose forms · 8 strengths
  1. Dose form (SCDF) Inhalation Powder RxCUI 2108327 No current FDA listing
    Clinical drug / strength (SCD) sodium 20 MG RxCUI 309548
  2. Dose form (SCDF) Inhalation Solution RxCUI 2108316 No current FDA listing
    Clinical drug / strength (SCD) sodium 10 MG/ML RxCUI 831246
  3. Dose form (SCDF) Metered Dose Inhaler RxCUI 746181 No current FDA listing
  4. Dose form (SCDF) Metered Dose Nasal Spray RxCUI 1797850 No current FDA listing
    Clinical drug / strength (SCD) sodium 5.2 MG/ACTUAT RxCUI 1797851
  5. Dose form (SCDF) Nasal Spray RxCUI 378374 No current FDA listing
    Clinical drug / strength (SCD) sodium 5.2 MG/ACTUAT RxCUI 849548
  6. Dose form (SCDF) Ophthalmic Solution RxCUI 378379 In current FDA listings
    Clinical drug / strength (SCD) sodium 20 MG/ML RxCUI 562108 sodium 40 MG/ML RxCUI 831109
  7. Dose form (SCDF) Oral Capsule RxCUI 378381 No current FDA listing
    Clinical drug / strength (SCD) sodium 100 MG RxCUI 831263
  8. Dose form (SCDF) Oral Solution RxCUI 378378 No current FDA listing
    Clinical drug / strength (SCD) sodium 20 MG/ML RxCUI 831261

Look up RxCUI 42612 in the RxCUI Atlas →

RxNorm is the U.S. National Library of Medicine’s normalized drug vocabulary. Its concept hierarchy can include forms that are not currently marketed; the status on each branch compares that concept with current FDA listings. RxCUIs identify vocabulary concepts, not individual packages or manufacturers.

🏷️ Sold under these brand names

Crolom Nasalcrom Gastrocrom

🏭 Manufacturers & labelers

A-S Medication Solutions 5 Preferred Pharmaceuticals Inc. 2 Proficient Rx LP 2 RPK Pharmaceuticals, Inc. 2 Sandoz Inc 2 Akorn 1

RxNorm drug class

Cromolyn Ophthalmic belongs to the Mast Cell Stabilizer class.

Pharmacologic class Mast Cell Stabilizer
Drug family (ATC) Antiallergic agents, excl. corticosteroids, Agents for dermatitis, excluding corticosteroids, Antiallergic agents, excl. corticosteroids

Classified by RxNorm RxClass — the U.S. National Library of Medicine's standardized drug-classification service (Established Pharmacologic Class from the FDA, the ATC drug family from the WHO, and mechanism of action). Reference only, not medical advice.

🔬 Where this comes from

Core label, product, RxNorm, safety, and utilization data on this page come from the sources identified below. AI-written, editorial, and licensed sections are labeled separately.

📄
FDA-filed drug labels (SPL) Uses, dosing, warnings & side effects from SPL records retrieved through openFDA; the linked representative set can be verified on DailyMed. ✓ Linked label effective Jan 25, 2022
🏭
Forms, brands & labelersAggregated from ingredient-matched FDA National Drug Code Directory product records for Cromolyn Ophthalmic.
📈
Real-world reportsThe FDA Adverse Event Reporting System (FAERS), served through openFDA.
🚨
Recalls & shortagesopenFDA drug-enforcement reports and the FDA drug-shortage database.
🧾 Clinical label set — FDA-filed SPL labels retained for Cromolyn Ophthalmic after exact ingredient or ingredient-combination matching and applicable route/form matching
Clinical labels in scope
6
NDC products indexed
14
Distinct labelers/manufacturers represented
6
Linked representative label
Akorn
Linked label effective
Jan 25, 2022
Composite sections available
12
Linked SPL Set ID
e604ed4d-d8a7-4f65-a386-b4bd6137d987
Linked SPL Document ID
2c91e02d-0a38-4225-b30d-249fd182568f
Open the linked representative label on DailyMed ↗
NDC package records associated with this linked SPL 1

How we combine label and product data

HelloPharmacist combines public FDA and NLM records; we don’t author the underlying clinical facts. We identified 6 FDA-filed SPL label sets within the page’s selected clinical scope after exact ingredient or ingredient-combination matching and applicable route/form matching. The representative label is the starting point for the displayed reference monograph; the 12 largest stored in-scope SPL records, which may include that representative, are compared section by section, and the longest available version of each section is retained. Forms, routes, brands, labelers, product-listed strengths, and product-record counts are aggregated separately from ingredient-matched FDA NDC Directory records; package records listed above are associated with the linked SPL; and the normalized concept hierarchy comes from NLM RxNorm.

Where a section is identified as AI-written, its plain-language text is generated from bounded label evidence. New draft drug pages remain in the admin review queue before first publication. Akorn is the representative DailyMed label linked for verification and dates; it is not the sole source used for the page.

This is general education, not medical advice — always consult your doctor or pharmacist about your medications and any medical condition. For the exact wording of the linked representative label, view that label on DailyMed; some displayed composite sections may come from other in-scope SPL labels. Learn how we use AI and our data sources & update cadence.