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What Are The Ingredients In Allergy Medicine?

Understanding Active And Inactive Allergy Medicine Ingredients

Dr. Lyssa Logue Profile Photo

Written by Dr. Lyssa Logue on October 11, 2021

Medically reviewed by Camille Freking, MS Pharmacology

If you have the misfortune of suffering through the uncomfortable symptoms associated with seasonal or perennial allergies, you know just how disruptive the constant sneezing, runny nose, and itchy, water eyes can be.

Patients who are considering taking allergy medicine to help manage their symptoms and improve their quality of life may find themselves asking “what are the active and inactive allergy medicine ingredients?”

What is the difference between active and inactive ingredients?

All allergy medications contain both active and inactive ingredients.

The U.S. Food and Drug Administration (FDA) has defined active ingredients as any component of a drug product that is intended to furnish pharmacological activity or other direct effect in the diagnosis, cure, mitigation, treatment, or prevention of disease, or to affect the structure or any function of the body of humans or animals.

Put more simply, active ingredients are the parts of an allergy medicine that improve your allergy symptoms directly.

Inactive ingredients are defined by the FDA as any component of a drug product other than the active ingredient.

Inactive ingredients play many different roles in allergy medications, including:

  • Preserving the medication by preventing the growth of bacteria and fungi
  • Helping the body to absorb the drug more easily by combining with an easily digestible substance like a fatty acid
  • Preventing a medication from being dissolved
  • Binding the ingredients together to give the medicine a cohesive shape
  • Masking the bitter taste of some medications to make them easier to swallow

What are the active ingredients in allergy medicine?

People experience allergy symptoms in response to exposure to an allergen. Allergens are typically harmless substances that trigger an unexpected immune response in some people.

People can experience seasonal allergies, which occur only at certain times of the year, perennial allergies, which occur year round, or both. Seasonal allergies are commonly associated with allergens like treat or plant pollen, while perennial allergies are linked to allergens like pet dander and dust mights.

Cetirizine HCl, the active ingredient in Zyrtec, is an over the counter medication that belongs to a class of drugs called antihistamines. Medications in this class block the effect of a substance called histamine that is naturally produced by the immune system in response to exposure to an allergen. The release of histamine typically triggers allergy symptoms like sneezing, itchy or watery eyes, runny nose, itchy throat, and itchy nose, but antihistamines can help reduce or stop this reaction.

Chlorpheniramine, the active ingredient in a drug called Chlor-Trimeton, also belongs to the antihistamine class of drugs. This active ingredient relieves symptoms associated with allergies, hay fever (allergic rhinitis), and the common cold, including sneezing, runny nose, red, itchy, or watery eyes, and scratchy nose or throat. Chlorpheniramine works to relieve the symptoms associated with allergies but does not prevent allergies from occurring.

Diphenhydramine HCl is a type of antihistamine that is used to relieve symptoms caused by hay fever (allergic rhinitis), allergies, or the common cold. The medication can help to relieve symptoms like runny nose, sneezing, congestion, and eyes that are red, itchy, irritated, and watery. Benadryl Allergy ULTRATAB Tablets are intended to treat symptoms of allergies and are most commonly used to relieve symptoms associated with acute seasonal allergies.

Loratadine is also an antihistamine and is sold under the brand names Claritin and Alavert. Like other antihistamines, loratadine treats symptoms of allergies; however, loratadine is only able to improve nasal symptoms of allergies, such as sneezing, runny nose, and itchy eyes, nose, and throat. The medication can also be used to reduce itching and redness caused by hives but cannot be used to treat other skin reactions that occur as a result of allergies. Loratadine is commonly combined with pseudoephedrine.

What are the inactive ingredients in allergy medication?

Each type of allergy medication contains different ingredients depending on the brand, formula, and specific product selected. However, some of the most common inactive ingredients found in allergy medication are included below:

Carnauba wax is a coating that is applied to many different tablets to make them easier to swallow. The wax consists primarily of fatty acid esters that create a slippery surface, which can help people who have difficulty swallowing pills.

Colloidal silicon dioxide, a naturally occurring mineral commonly referred to as sand or quartz, is found in the earth’s crust and is a normal part of the human diet. Silicon dioxide and other silicates are commonly found in animals, plants, and water that we consume each day. Silicates like colloidal silicon dioxide are typically added to medications as an inactive ingredient so that they can function as an anti-caking agent, disintegrant, adsorbent, or glidant that allows powder to flow freely when a tablet is processed by the body.

Croscarmellose sodium is a type of salt that is commonly used as a disintegrant in some types of allergy medicine. Unlike other types of cellulose, which consist of short, individual fibers, croscarmellose sodium forms long, thick chains. When added to medications as an inactive ingredient, croscarmellose sodium helps tablets and capsules to dissolve quickly in the stomach so that the active ingredient can be absorbed quickly and can provide relief.

Dyes are commonly used in allergy medications to give the drugs a more appealing color. Dyes may be synthetic or natural, but the majority of medications contain synthetic dyes like D&C red no. 27 aluminum lake. Lake dyes are formed by causing a reaction between straight dyes, such as D&C red no. 27, and a type of salt, such as aluminum.

Dibasic calcium phosphate is typically found in the form of a salt and is classified as a diluent. Diluents are inactive ingredients that add bulk to a medication, making the final product easier to handle and swallow. Diluents also make medications more stable. Because the active ingredient of a medication is often included in a small amount, medications would be too small to handle properly without inactive ingredients like diluents.

Hypromellose is a commonly used cellulose that is used in allergy medicines to control the timing of the active ingredient’s release. While the active ingredient needs to start working quickly, it also needs to last in the body for long enough to provide relief between doses. If medications wear off too quickly, people end up taking too much of an active ingredient, potentially causing dangerous side effects.

Lactose is a type of milk sugar that is sourced from dairy products. Made up of one molecule of galactose and one molecule of glucose, lactose is highly compressible. This inactive ingredient is commonly added to allergy medications to help them maintain their shape and hold a form. Lactose may be listed on medication labels as lactose hydrous, lactose anhydrous, lactose monohydrate, or lactose spray-dried. People with a dairy allergy or lactose intolerance should not use products that contain lactose.

Magnesium stearate is a common inactive ingredient that is used as a gliding agent, meaning it prevents different ingredients from clumping together in a way that is not uniform. Additionally, adding magnesium stearate to a medication reduces the likelihood that the drug will stick to the machinery on which it was produced. Additionally, magnesium stearate also helps to improve the consistency of medication capsules and delay the rate at which the active ingredients are broken down and absorbed.

Microcrystalline cellulose is a form of cellulose that is used as an inactive ingredient because of its ability to make allergy medication tablets hard but easily dissolvable.

Polyethylene glycol can serve many different functions as an inactive ingredient, including acting as a solvent, capsule, tablet lubricant, plasticizer, and surfactant. Allergy medications commonly incorporate polyethylene glycol into their tablets because it makes the pills easier to swallow.

Polysorbate 80 is a common solubilizing agent and excipient that can be used for a number of different purposes in allergy medications. When included in tablets, this ingredient typically helps to stabilize the medication to help ensure that it is properly absorbed.

Titanium dioxide is a naturally occurring mineral that is commonly used in medications as a pigment for the coatings on allergy medication tablets.


Each allergy medicine contains different active and inactive ingredients. Common active ingredients in allergy medicine include cetirizine HCl, chlorpheniramine, diphenhydramine HCl, and loratadine. Common inactive ingredients in allergy medicines include carnauba wax, colloidal silicon dioxide, croscarmellose sodium, natural and artificial dyes, dibasic calcium phosphate, hypromellose, lactose, magnesium stearate, microcrystalline cellulose, polyethylene glycol, polysorbate 80, and titanium dioxide.