The Science Behind How Do Lozenges Work?

October 7, 2025 •

5 min read

Dating back to the 20th century, lozenges have served as a popular and effective oral medication. This easy-to-use delivery system is designed to provide targeted, localized relief for mouth and throat irritations, but many people are unaware of the underlying pharmacology that explains how do lozenges work. Beyond just local effects, certain types of lozenges can also deliver active ingredients systemically, providing wider therapeutic benefits throughout the body.

Quick Summary

Lozenges function by dissolving slowly in the mouth, delivering medication for local action on the oral cavity or systemic absorption via the buccal mucosa. They provide soothing relief for sore throats, suppress coughs, and can administer systemic drugs by bypassing the digestive tract. Their slow dissolution profile and pleasant taste enhance patient adherence.

Key Points

Slow Dissolution for Sustained Release: Lozenges are designed to dissolve slowly, allowing for a gradual, continuous release of active ingredients into the mouth and throat over a period of several minutes.
Dual Action for Local and Systemic Effects: Depending on their formulation, lozenges can either provide local, targeted relief for the throat and mouth or deliver drugs for systemic absorption via the oral mucosa, bypassing the digestive system.
Multiple Therapeutic Mechanisms: Lozenges can work through several mechanisms, including demulcent (coating and soothing), anesthetic (numbing pain), antiseptic (killing germs), and antitussive (suppressing coughs) properties.
Improved Patient Adherence: The pleasant taste, variety of formulations (hard, soft, chewable), and ease of administration make lozenges highly acceptable for patients, especially children and the elderly who have difficulty swallowing pills.
Bypasses First-Pass Metabolism: For systemic drugs, mucosal absorption through the cheek or under the tongue allows the medication to enter the bloodstream directly, avoiding the liver's first-pass effect and leading to higher bioavailability and faster action.
Stimulates Saliva for Added Relief: The act of sucking on a lozenge increases saliva production, which helps lubricate and moisten a dry or scratchy throat, further enhancing the soothing effect.
Versatile and Convenient Dosage Form: Available in different types and bases, lozenges are portable, require no water, and can deliver a wide variety of medications, from vitamins to nicotine replacement therapy.

The Dual Mechanism of Action: Local vs. Systemic

At its core, a lozenge is a solid oral dosage form that releases medicine as it dissolves in the mouth. This slow dissolution is the key to its effectiveness, allowing for a sustained release of the active ingredients over a period of time. Depending on the formulation, this process can lead to either a local effect, concentrating the medication in the mouth and throat, or a systemic effect, where the drug is absorbed into the bloodstream.

Local Therapeutic Effects

For common ailments like sore throats and coughs, the primary mechanism is a local, topical effect. As the lozenge dissolves, it releases a continuous flow of medicated saliva that bathes the irritated tissues of the mouth and throat.

Here's how specific ingredients achieve their local effects:

Demulcent Action: Ingredients like honey, pectin, and glycerin act as demulcents. They coat the pharynx and other oral tissues, providing a soothing, protective layer that relieves irritation and reduces inflammation. The increased saliva production from sucking on the lozenge further lubricates a dry or scratchy throat.
Anesthetic Action: Mild local anesthetics such as benzocaine or lidocaine are included in some lozenges to numb the nerve endings in the throat. This temporarily blocks pain signals, providing rapid relief from a sore throat, particularly when swallowing.
Antiseptic Action: Certain lozenges contain antimicrobial agents like amylmetacresol or cetylpyridinium chloride. These agents can help kill germs that cause mouth and throat infections. However, it is important to remember that most common colds are viral, so antibacterial lozenges will not cure the underlying viral infection.
Antitussive Action: Some lozenges include cough suppressants like dextromethorphan, which acts on the brain to inhibit the cough reflex. Others use menthol, which creates a cooling sensation that soothes the throat and can reduce the urge to cough.

Systemic Absorption through the Oral Mucosa

While many lozenges are for local relief, others are engineered for systemic drug delivery. In this case, the active drug is absorbed directly through the highly vascularized oral mucosa (the lining of the mouth) into the bloodstream. This delivery method is beneficial for several reasons:

Bypasses First-Pass Metabolism: The drug avoids the gastrointestinal tract and the liver's first-pass metabolic process, which can break down some medications before they reach systemic circulation. This can lead to increased bioavailability and a more efficient dose.
Rapid Onset of Action: With direct absorption into the bloodstream, the therapeutic effect can be achieved much more quickly than with traditional oral tablets that must be digested and absorbed via the stomach. Examples include nicotine replacement therapy lozenges and certain pain medications.

Different Types of Lozenges for Varied Effects

Lozenges are not a one-size-fits-all product. They come in various forms, each with a different base material and manufacturing process tailored for a specific dissolution profile.

Hard Lozenges: These are essentially medicated hard candies, made from a base of sugar and corn syrup. They are processed at high temperatures and must contain heat-stable drugs. Their slow, uniform dissolution over 5 to 10 minutes makes them ideal for prolonged topical effects on the throat.
Soft Lozenges (Pastilles): With a softer, more pliable texture, soft lozenges often use a base of acacia or polyethylene glycol (PEG). They provide a more immediate soothing effect compared to hard lozenges, and can be designed for either slow dissolution or chewing.
Chewable Lozenges: Made from a glycerinated gelatin base, these have a chewy, gummy texture and are often fruit-flavored to mask the taste of the drug. They are particularly popular for pediatric patients and can be designed for systemic absorption through the gastrointestinal tract.
Compressed Lozenges (Troches): Manufactured using a compression method similar to tablets, these are used for heat-sensitive ingredients. They are harder and designed for slow erosion rather than disintegration.

Comparison of Lozenge Types


Feature	Hard Lozenges	Soft Lozenges (Pastilles)	Chewable Lozenges	Compressed Lozenges (Troches)
Texture	Hard, glassy, candy-like	Softer, flexible, sometimes chewy	Gummy, chewable	Hard, compressed tablet
Base Ingredients	Sugar (sucrose), corn syrup	Polyethylene glycol (PEG), acacia, gelatin	Glycerinated gelatin	Dextrose, fillers, binders
Dissolution Time	5–10 minutes, slow erosion	Variable, from slow dissolution to quick chew	Rapid, chewed for quicker effect	Slow, uniform erosion
Best Use Case	Prolonged local relief, heat-stable drugs	Quick local soothing, versatile drug types	Pediatric patients, GI absorption	Heat-sensitive drugs, sustained local release
Preparation	High-temperature cooking, molding	Molding, low heat required	Molding, low heat required	High-compression tableting

Advantages and Considerations for Lozenges

In addition to their mechanism of action, lozenges offer several practical advantages over other oral medications.

Ease of Administration: Lozenges are an excellent option for patients who have difficulty swallowing pills, including pediatric, geriatric, and special-needs populations.
Convenience: They do not require water to take, making them easy to use on the go.
Improved Patient Compliance: The pleasant taste and texture of lozenges can improve patient adherence to treatment, particularly with children.
Targeted Delivery: For local conditions like sore throats, lozenges deliver the medicine directly to the affected area, providing concentrated relief.
Bypasses Digestion: For systemic effects, absorption through the oral mucosa avoids the first-pass metabolism, potentially increasing the drug's effectiveness.

Despite these benefits, there are important considerations. Lozenges, especially those that look and taste like candy, pose a choking hazard to small children and must be kept out of their reach. For antibacterial lozenges, it's crucial to understand they are ineffective against viral causes of sore throats. Overuse of certain types, such as those with menthol, could potentially prolong a cough.

Conclusion

Lozenges are a versatile and effective drug delivery system rooted in sophisticated pharmaceutical science. Their success lies in their controlled dissolution, which can be engineered to produce targeted local relief for common throat and mouth irritations, or rapid systemic effects by leveraging the oral mucosa's absorptive properties. By understanding how do lozenges work—from the soothing demulcent action of a honey lozenge to the rapid systemic delivery of a nicotine troche—consumers and healthcare professionals can make informed choices to achieve optimal therapeutic outcomes. This convenient, non-invasive dosage form continues to be a staple in modern pharmacology, offering a patient-friendly alternative for a wide range of medical needs. For further insights into oral drug delivery, authoritative resources like the National Institutes of Health (NIH) offer extensive research and articles on oral transmucosal delivery systems.

Frequently Asked Questions

The dissolution time depends on the type of lozenge. Hard lozenges typically take 5 to 10 minutes to dissolve slowly, while soft or chewable lozenges may dissolve or be chewed more quickly.

Lozenges are often considered more effective for sore throats than sprays and gargles because their slow dissolution provides a continuous stream of medication that bathes the throat for a prolonged period.

Lozenges do not cure the underlying infection causing a sore throat. Instead, they are used to manage and relieve symptoms like pain, dryness, and irritation while your body fights the infection.

The terms 'lozenge' and 'troche' are often used interchangeably. Generally, a troche refers to a compressed tablet lozenge, which is a harder, non-disintegrating type made under high pressure, unlike the molded hard candy lozenge.

Lozenges can pose a choking hazard for young children, so it is generally recommended to use them only for older children who can safely handle hard candies. Always consult a doctor for children under 6.

Menthol is used in lozenges to provide a cooling sensation that soothes the throat. It can also help reduce the urge to cough and loosen phlegm.

For systemic effects, the active ingredient in a lozenge is absorbed through the oral mucosa (buccal or sublingual routes). This bypasses digestion and the liver's first-pass metabolism, allowing the drug to enter the bloodstream directly.

Sugar-free lozenges function similarly but use sugar substitutes like sorbitol or mannitol. They are beneficial for diabetics and individuals concerned about sugar intake, while still providing the same local and systemic effects.