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Medical Disclaimer: This information is for educational purposes only and is not a substitute for professional medical advice.
Standardized Chemical Allergen [EPC]
Carboxymethylcellulose Sodium, Unspecified Form is a versatile cellulose derivative used primarily as an ophthalmic lubricant and a standardized chemical allergen in diagnostic testing. It belongs to the classes of Standardized Chemical Allergens and Food Allergenic Extracts.
Name
Carboxymethylcellulose Sodium, Unspecified Form
Raw Name
CARBOXYMETHYLCELLULOSE SODIUM, UNSPECIFIED FORM
Category
Standardized Chemical Allergen [EPC]
Drug Count
9
Variant Count
11
Last Verified
February 17, 2026
RxCUI
1188426, 579907, 998666, 1547948, 2106821
UNII
K679OBS311, DO80M48B6O, LMI26O6933, T3CHA1B51H, J64922108F, MLT3645I99, S54S8B99E8, 731DCA35BT, 2DI9HA706A, 1HG84L3525, V1V998DC17, 4632WW1X5A, 1C89KKC04E, A2I8C7HI9T, 2166IN72UN, I9O0E3H2ZE, ER0CTH01H9, 339NCG44TV, E1NC1JVS3O, 5KQR6FTT0D
About Carboxymethylcellulose Sodium, Unspecified Form
Carboxymethylcellulose Sodium, Unspecified Form is a versatile cellulose derivative used primarily as an ophthalmic lubricant and a standardized chemical allergen in diagnostic testing. It belongs to the classes of Standardized Chemical Allergens and Food Allergenic Extracts.
Detailed information about Carboxymethylcellulose Sodium, Unspecified Form
This page is for informational purposes only and does not replace medical advice. Consult a qualified healthcare professional before using any medication containing Carboxymethylcellulose Sodium, Unspecified Form.
Carboxymethylcellulose Sodium (CMC), often referred to in clinical settings as cellulose gum or sodium CMC, is a high-molecular-weight polymer derived from natural cellulose. In the context of the 'Unspecified Form,' this designation typically refers to various viscosity grades and molecular weights of the sodium salt of polycarboxymethyl ether of cellulose. Pharmacologically, it is classified as a Standardized Chemical Allergen [EPC] and a Non-Standardized Food Allergenic Extract [EPC], though it is most widely recognized by the general public as a lubricant in ophthalmic (eye) preparations.
As a Standardized Chemical Allergen, CMC is utilized by immunologists and allergists to identify hypersensitivity reactions in patients who may be reactive to pharmaceutical excipients (inactive ingredients) or food additives. Because CMC is ubiquitous in processed foods, pharmaceuticals, and cosmetics, identifying a specific allergy to this compound is critical for patient safety. It belongs to a class of drugs known as cellulose derivatives, which are characterized by their ability to retain water, provide viscosity, and form protective films on mucosal surfaces. The FDA has long recognized CMC as 'Generally Recognized as Safe' (GRAS) for use in food and as an inactive ingredient in many oral and topical medications. However, its use as an active ingredient in ophthalmic lubricants was established through the FDA's Over-the-Counter (OTC) Monograph process, confirming its efficacy in treating dry eye symptoms.
The mechanism of action for Carboxymethylcellulose Sodium varies depending on its clinical application. When used as an ophthalmic lubricant (artificial tears), CMC works through its physical and rheological properties rather than a traditional biochemical receptor-mediated pathway. Upon application to the ocular surface, the CMC molecule binds to the corneal epithelial cells via glucopyranose receptors. This binding increases the residence time of the lubricant on the eye, providing a protective, hydrophilic (water-loving) film that stabilizes the tear film. This film reduces evaporation and provides a mechanical cushion between the eyelid and the cornea, which is essential for patients with keratoconjunctivitis sicca (dry eye syndrome).
In its role as a Standardized Chemical Allergen, the mechanism is diagnostic. When applied to the skin (patch testing) or administered via intradermal injection in a controlled clinical setting, CMC acts as a potential hapten or antigen. In sensitized individuals, the immune system—specifically T-cells or IgE antibodies—recognizes the CMC polymer, triggering a localized inflammatory response. This allows clinicians to confirm a diagnosis of contact dermatitis or systemic hypersensitivity to this specific cellulose derivative.
Carboxymethylcellulose Sodium, Unspecified Form, is indicated for several distinct clinical purposes:
CMC is available in a wide array of formulations due to its versatility:
> Important: Only your healthcare provider can determine if Carboxymethylcellulose Sodium, Unspecified Form is right for your specific condition.
For the treatment of mild to moderate dry eye symptoms, the standard dosage is 1 to 2 drops in the affected eye(s) as needed. Patients with chronic ocular surface disease may require more frequent application, sometimes up to 4 to 6 times daily. If using a high-viscosity gel form, application is typically limited to once or twice daily, often before bedtime, due to potential temporary blurring of vision.
Dosage for diagnostic purposes is highly individualized and must be performed by a specialist. For patch testing, a small amount of the standardized extract (often 10% in petrolatum) is applied to the back under an occlusive dressing for 48 hours. For intradermal testing, minute volumes (e.g., 0.02 mL) of a sterile solution are injected into the dermis to observe for a wheal-and-flare reaction.
Carboxymethylcellulose Sodium is generally considered safe for use in children when used as an ophthalmic lubricant. The dosage is typically the same as the adult dose (1-2 drops as needed). However, safety and efficacy for diagnostic allergy testing in children under the age of 6 have not been extensively documented in large-scale clinical trials; therefore, pediatric allergy testing must be conducted under strict medical supervision.
Because Carboxymethylcellulose Sodium is not systemically absorbed, no dosage adjustments are required for patients with renal (kidney) impairment. There is no risk of accumulation in the kidneys.
No dosage adjustments are necessary for patients with hepatic (liver) impairment, as the drug does not undergo hepatic metabolism or biliary excretion.
No specific dosage reductions are recommended for geriatric patients. However, elderly patients may be more prone to dry eye symptoms due to age-related changes in tear production and may require more frequent application of the lubricant.
Store at room temperature (15°C to 30°C or 59°F to 86°F). Protect from freezing and excessive heat. For preservative-free single-use vials, discard the vial immediately after a single use, even if some solution remains.
Since CMC is primarily used on an 'as-needed' basis for symptom relief, a missed dose is not clinically significant. Simply apply the drops when you remember or when symptoms of dryness recur. Do not 'double up' the dose to make up for a missed application.
An overdose of Carboxymethylcellulose Sodium via the ophthalmic route is highly unlikely to cause systemic toxicity. Excessive application to the eye may result in temporary blurred vision or a sticky sensation on the eyelids. If the solution is accidentally ingested, it generally passes through the digestive tract without harm, though large quantities might cause mild gastrointestinal upset or a laxative effect. In case of accidental ingestion by a child, contact a Poison Control Center as a precaution.
> Important: Follow your healthcare provider's dosing instructions. Do not adjust your dose without medical guidance.
When used as an ophthalmic lubricant, the most frequently reported side effects are localized to the eye and are generally transient. These include:
While Carboxymethylcellulose Sodium is exceptionally safe, systemic hypersensitivity (anaphylaxis) has been documented in rare clinical case reports, particularly when the substance is used as an excipient in injectable medications.
> Warning: Stop taking Carboxymethylcellulose Sodium, Unspecified Form and call your doctor immediately if you experience any of these:
Prolonged use of Carboxymethylcellulose Sodium is generally considered safe and is often necessary for the management of chronic dry eye. However, long-term use of multi-dose bottles containing certain preservatives (like Benzalkonium Chloride) can lead to corneal epithelial damage or 'medicamentosa' (drug-induced inflammation). For patients requiring long-term therapy more than 4 times daily, preservative-free formulations are strongly recommended to avoid these chronic ocular surface changes.
There are currently no FDA Black Box Warnings for Carboxymethylcellulose Sodium, Unspecified Form. It is regarded as one of the safest pharmacological agents in ophthalmic and diagnostic use.
Report any unusual symptoms to your healthcare provider. You may also report side effects to the FDA at 1-800-FDA-1088.
Carboxymethylcellulose Sodium, Unspecified Form, is intended for topical ophthalmic or diagnostic use only. It should not be injected into the eye or taken orally unless specifically directed by a healthcare professional in a clinical setting. Patients must ensure that the product is not contaminated; if the solution changes color or becomes cloudy, it should be discarded immediately. Furthermore, if symptoms of dry eye worsen or persist for more than 72 hours, a comprehensive eye examination is necessary to rule out underlying conditions such as Sjögren's syndrome or bacterial keratitis.
No FDA black box warnings for Carboxymethylcellulose Sodium, Unspecified Form.
Although CMC is used as a diagnostic allergen, it can also cause unexpected allergic reactions. Patients with a known history of sensitivity to other cellulose derivatives (such as methylcellulose or hydroxypropyl methylcellulose) should exercise caution. Rare cases of systemic anaphylaxis have occurred when CMC was present as an excipient in corticosteroid injections. If you have a history of severe drug allergies, inform your doctor before undergoing testing with CMC.
To avoid serious ocular infections, the tip of the dispensing container must never touch any surface, including the eye itself. Use of contaminated eye drops can lead to corneal ulcers and potential vision loss. Multi-dose bottles should be discarded within the timeframe specified by the manufacturer (usually 30 to 90 days after opening).
Some formulations of CMC contain preservatives that can be absorbed by soft contact lenses. Generally, it is advised to remove contact lenses before instilling the drops and wait at least 15 minutes before reinserting them. However, many 'preservative-free' CMC products are specifically marketed as safe for use with contact lenses; always check the specific product labeling.
There are no specific laboratory monitoring requirements (such as blood counts or liver enzymes) for the use of Carboxymethylcellulose Sodium due to its lack of systemic absorption. However, patients using it for dry eye should have regular ophthalmic examinations to monitor corneal health and tear film stability. For those undergoing allergy testing, monitoring of vital signs during the procedure is standard practice to manage any potential systemic reactions.
Carboxymethylcellulose Sodium may cause transient blurring of vision immediately after application. Patients should not drive, operate heavy machinery, or engage in any hazardous activities until their vision has cleared completely. This usually occurs within a few minutes but may take longer with high-viscosity gel formulations.
There are no known interactions between alcohol consumption and the use of topical Carboxymethylcellulose Sodium. Because the drug is not systemically absorbed, alcohol does not affect its pharmacokinetics or pharmacodynamics.
There is no risk of withdrawal syndrome or rebound effect upon discontinuing Carboxymethylcellulose Sodium. However, symptoms of dry eye or ocular irritation are likely to return if the underlying cause of the dryness has not been addressed.
> Important: Discuss all your medical conditions with your healthcare provider before starting Carboxymethylcellulose Sodium, Unspecified Form.
There are no known absolute contraindications for combining Carboxymethylcellulose Sodium with other medications. Because it acts physically rather than chemically and is not absorbed into the bloodstream, it does not interfere with the systemic action of other drugs.
While no serious systemic interactions exist, the physical presence of CMC on the eye can affect the absorption of other topical ophthalmic medications. If CMC is applied simultaneously with a medicated eye drop (such as a glaucoma medication or antibiotic), it may create a physical barrier or dilute the active medication, potentially reducing its efficacy.
Management: Always wait at least 5 to 10 minutes between the application of Carboxymethylcellulose Sodium and any other ophthalmic medication. Generally, the medicated drop should be applied first, followed by the lubricant.
If you are using both CMC drops and an ophthalmic ointment, the drops should be used first. Ointments have a thick, petrolatum base that will prevent the CMC drops from reaching the corneal surface if applied afterward.
There are no known food interactions with topical Carboxymethylcellulose Sodium. When CMC is used as a food additive, it is considered inert and does not interact with the absorption of nutrients, although as a soluble fiber, it could theoretically slow the absorption of some highly lipophilic substances if consumed in very large quantities.
No interactions have been documented between Carboxymethylcellulose Sodium and herbal supplements such as St. John's Wort, Ginkgo Biloba, or Valerian root. The localized nature of CMC's action precludes systemic interaction with these substances.
Carboxymethylcellulose Sodium does not interfere with standard blood or urine laboratory tests. However, its presence on the ocular surface might interfere with certain specialized ophthalmic diagnostic tests, such as tear film osmolarity testing or certain types of corneal staining, if applied immediately before the test. Inform your ophthalmologist if you have used lubricant drops on the day of your eye exam.
> Important: Tell your doctor about ALL medications, supplements, and herbal products you are taking.
Carboxymethylcellulose Sodium, Unspecified Form, must NEVER be used in the following circumstances:
Conditions requiring careful risk-benefit analysis include:
Patients who are allergic to other cellulose ethers may exhibit cross-sensitivity to Carboxymethylcellulose Sodium. These related substances include:
If you have had a reaction to 'artificial tears' in the past, it is vital to identify which specific cellulose derivative was used to avoid a cross-reactive inflammatory response.
> Important: Your healthcare provider will evaluate your complete medical history before prescribing Carboxymethylcellulose Sodium, Unspecified Form.
Carboxymethylcellulose Sodium is not systemically absorbed following topical ophthalmic or oral administration. Consequently, there is no measurable exposure to the developing fetus. There are no known teratogenic effects associated with CMC. It is widely used by pregnant women for the relief of dry eye, which can be exacerbated by hormonal changes during pregnancy. As with all medications, use during pregnancy should be discussed with a healthcare provider, but the risk profile is considered negligible.
It is not known whether CMC is excreted in human milk; however, because there is no systemic absorption from the eye or gut, it is physiologically impossible for clinically significant amounts to reach the breast milk. There are no known risks to the nursing infant. Carboxymethylcellulose Sodium is considered compatible with breastfeeding.
CMC is frequently used in children to treat ocular irritation caused by allergies, screen time, or environmental factors. It is generally safe for all age groups. However, parents should administer the drops to ensure the dropper tip does not touch the child's eye. For diagnostic allergy testing, the safety and efficacy have not been established in infants, and such procedures should only be conducted by a pediatric allergist.
Elderly patients often suffer from decreased tear production (aqueous deficient dry eye) and may benefit significantly from CMC. No dosage adjustments are required. However, elderly patients with arthritic hands may find it difficult to squeeze small dropper bottles and may require assistive devices or preservative-free vials that are easier to manipulate. There is no increased risk of systemic side effects in the elderly due to the lack of absorption.
No adjustments are necessary. CMC does not enter the systemic circulation and therefore does not place any burden on the kidneys. It is safe for patients on hemodialysis or those with end-stage renal disease (ESRD).
No adjustments are necessary. CMC is not processed by the liver. It is safe for patients with cirrhosis or other forms of hepatic dysfunction.
> Important: Special populations require individualized medical assessment.
Carboxymethylcellulose Sodium is a long-chain polymer of β-D-glucose units. Its primary pharmacological action is mucoadhesion. The polymer contains multiple carboxyl groups (-COOH) that interact with the mucin layer of the tear film and the glycocalyx of the corneal epithelial cells. By mimicking the action of natural mucins, CMC stabilizes the tear film and increases the 'break-up time' (TBUT), which is a clinical measure of how long the tear film remains intact on the eye. At the molecular level, it provides a protective matrix that traps water, reducing the osmolarity of the tear film, which is often pathologically high in dry eye patients.
The dose-response relationship for CMC is related to its viscosity. Higher concentrations (e.g., 1.0%) provide longer-lasting relief but cause more significant temporary blurring than lower concentrations (0.5%). The onset of effect is immediate upon instillation. The duration of effect typically lasts between 30 minutes and 2 hours, depending on the severity of the patient's tear deficiency and environmental conditions (e.g., humidity, wind).
| Parameter | Value |
|---|---|
| Bioavailability | 0% (Topical/Oral) |
| Protein Binding | N/A (Not absorbed) |
| Half-life (Ocular) | 15–45 minutes (Retention time) |
| Tmax | Immediate (Local) |
| Metabolism | None |
| Excretion | Nasolacrimal drainage / Fecal (if ingested) |
Carboxymethylcellulose Sodium belongs to the therapeutic class of Ophthalmic Lubricants and the diagnostic class of Standardized Chemical Allergens. It is often grouped with other artificial tears such as Polyvinyl Alcohol, Glycerin, and Propylene Glycol.
Medications containing this ingredient
Common questions about Carboxymethylcellulose Sodium, Unspecified Form
Carboxymethylcellulose Sodium is primarily used as an active ingredient in artificial tears to provide temporary relief from dry eye symptoms, such as burning, itching, and redness. It works by coating the eye with a protective, moisturizing film that mimics natural tears. Additionally, in clinical allergy settings, it is used as a standardized allergen to help doctors diagnose hypersensitivity to certain food additives or drug inactive ingredients. Because it is highly effective at retaining moisture, it is also found in various skin care products and wound dressings. Always consult your doctor to ensure you are using the correct form for your specific needs.
The most common side effects are localized to the eye and include temporary blurred vision, a mild stinging sensation, and watery eyes immediately after application. Some users may also notice a slight crusting on the eyelids as the solution dries over time. These effects are usually mild and disappear within a few minutes as the drops spread across the eye surface. If you experience persistent eye pain, significant redness, or vision changes that do not go away, you should stop using the drops and contact an eye care professional. Serious systemic side effects are extremely rare because the drug is not absorbed into the bloodstream.
Yes, there are no known interactions between alcohol and Carboxymethylcellulose Sodium. Since this medication is applied topically to the eye or used as a diagnostic skin test, it does not enter your systemic circulation in significant amounts. Therefore, alcohol consumption does not affect how the medication works, nor does the medication increase the effects of alcohol. However, it is always important to maintain overall health, as excessive alcohol can sometimes contribute to systemic dehydration, which might indirectly worsen dry eye symptoms. If you have concerns, discuss your lifestyle habits with your healthcare provider.
Carboxymethylcellulose Sodium is generally considered very safe during pregnancy. Because the polymer is not absorbed into the mother's bloodstream from the eye or the digestive tract, there is no way for the medication to reach the developing fetus. It has a long history of use and no known links to birth defects or other pregnancy complications. Many pregnant women use these drops to manage 'pregnancy-induced dry eye' caused by hormonal shifts. However, it is always a best practice to inform your obstetrician about any over-the-counter products you are using during pregnancy.
The effects of Carboxymethylcellulose Sodium are almost instantaneous. As soon as the drops are instilled into the eye, they begin to lubricate the ocular surface and provide relief from dryness and irritation. While the initial soothing effect is immediate, the duration of relief can vary from 30 minutes to several hours depending on the concentration of the product and the severity of your dry eye. For diagnostic allergy testing, the results are not immediate; a patch test typically requires 48 to 72 hours for a reaction to develop. For daily eye lubrication, you can use the drops as often as needed throughout the day.
Yes, you can stop using Carboxymethylcellulose Sodium at any time without experiencing withdrawal symptoms or physical dependence. It is not a habit-forming medication and does not affect the body's internal chemistry. However, if you are using it to manage a chronic condition like dry eye syndrome, your symptoms (such as grittiness, redness, and discomfort) will likely return once you stop using the lubricant. If you find that you need to use the drops constantly, it is a good idea to see an eye doctor to determine if there is an underlying cause that requires a different type of treatment.
If you are using Carboxymethylcellulose Sodium on a regular schedule and miss a dose, simply apply the drops as soon as you remember. If it is almost time for your next scheduled application, skip the missed dose and resume your normal routine. Because this medication is used primarily for symptom relief and is not systemically active, missing a dose does not pose any health risks; it simply means your eyes may feel dry or irritated for a longer period. Do not use extra drops to 'make up' for a missed dose, as this will only result in temporary blurred vision or wasted product.
No, Carboxymethylcellulose Sodium does not cause weight gain. It is not a hormone, it does not affect your metabolism, and it is not absorbed into the body's systemic circulation. Even if small amounts are swallowed after being applied to the eye, the substance is a non-caloric fiber that passes through the digestive system without being digested or stored as fat. There is no clinical evidence linking the topical or oral use of CMC to changes in body weight or appetite. If you are experiencing unexplained weight gain, you should consult your doctor to investigate other potential causes.
Carboxymethylcellulose Sodium can generally be used alongside other medications, but timing is important for eye drops. If you are using other ophthalmic medications, such as drops for glaucoma or infections, you should wait at least 5 to 10 minutes between products to prevent the lubricant from washing out the active medication. For systemic medications taken by mouth, there are no known interactions with CMC eye drops. Always provide your healthcare provider with a full list of all medications, including vitamins and herbal supplements, to ensure there are no physical interactions that could reduce the effectiveness of your treatments.
Yes, Carboxymethylcellulose Sodium is widely available as a generic product and is the active ingredient in many store-brand 'Artificial Tears' or 'Lubricant Eye Drops.' Generic versions are required by the FDA to have the same quality and efficacy as brand-name products like Refresh or TheraTears. You can often find it in various strengths, such as 0.5% for mild dryness or 1.0% for more intensive relief. When buying generic versions, check if the product is 'preservative-free' if you have sensitive eyes or plan to use the drops more than four times a day.