Can antihistamines cause a sore throat?: Understanding the Connection Between Allergy Medication and Throat Irritation

October 12, 2025 •

4 min read

According to the FDA, common side effects of antihistamines like cetirizine include a sore throat and dry mouth. While effective for allergy relief, these medications can sometimes cause throat discomfort, and it's important to understand why and how to manage it.

Quick Summary

Antihistamines can cause a sore throat primarily by inducing dry mouth, which irritates the throat's mucous membranes. This side effect is more common with first-generation antihistamines, but can occur with newer versions. Management involves hydration and using throat lozenges, or potentially switching medications with a doctor's guidance.

Key Points

Drying Effect: Antihistamines can cause a sore throat by drying out mucous membranes, leading to throat irritation.
Dry Mouth (Xerostomia): The primary mechanism is the reduction of saliva production due to the medication's anticholinergic properties.
First vs. Second Generation: Older, first-generation antihistamines (like Benadryl) are more likely to cause significant dry mouth and a sore throat than newer, second-generation options (like Zyrtec or Allegra).
Management Strategies: Staying well-hydrated, using a humidifier, and sucking on lozenges or ice chips can help alleviate the symptoms.
When to See a Doctor: Seek medical advice if the sore throat is severe, persistent, or accompanied by more serious symptoms.
Hydration is Key: Drinking plenty of water is the most straightforward and effective way to combat the drying effect and soothe a scratchy throat.

While antihistamines are a mainstay for managing allergy symptoms, a lesser-known side effect for some individuals is the development of a sore or irritated throat. The discomfort isn't a direct result of the active ingredients attacking the throat, but rather a secondary symptom caused by a significant reduction in saliva and mucus production. This drying effect leaves the throat's delicate tissues parched and vulnerable to irritation, creating a feeling of scratchiness or soreness.

The Mechanism Behind Antihistamine-Induced Sore Throat

Antihistamines work by blocking the effects of histamines, the chemicals your body releases during an allergic reaction. However, in doing so, some antihistamines also have an anticholinergic effect. This means they interfere with acetylcholine, a neurotransmitter involved in several bodily functions, including the stimulation of saliva production.

By blocking acetylcholine receptors, especially in the salivary glands, antihistamines can significantly reduce salivary flow. This condition, known as xerostomia or dry mouth, is the primary reason for a sore throat developing after taking the medication. Saliva plays a crucial role in maintaining oral and throat health by:

Washing away food debris and irritants.
Lubricating the throat tissues.
Neutralizing acids and protecting against bacteria.

With decreased saliva, the throat can become dry, leading to irritation, discomfort, and a persistent, scratchy sensation. A subsequent, instinctive response to this dryness is often a cough, which can further exacerbate the soreness.

First-Generation vs. Second-Generation Antihistamines

The likelihood and severity of anticholinergic side effects like dry mouth and sore throat differ between the two main types of antihistamines. The difference lies in their chemical structure and how they interact with different receptors in the body.

First-Generation (Older) Antihistamines

First-generation antihistamines, such as diphenhydramine (Benadryl), are known for their strong anticholinergic properties. This means they more readily block acetylcholine, leading to more pronounced side effects like drowsiness, constipation, and significant dry mouth, which directly contributes to a sore throat. These medications are older, less selective, and more likely to cause these unwanted drying effects.

Second-Generation (Newer) Antihistamines

Newer, second-generation antihistamines, including cetirizine (Zyrtec), loratadine (Claritin), and fexofenadine (Allegra), are less likely to cause these anticholinergic effects. They are designed to be more selective in blocking histamine receptors, reducing the risk of a dry mouth. However, this does not mean the side effect is impossible. Case reports and clinical data still list sore throat as a potential, albeit less common, side effect for these medications.

Comparing Antihistamines and Side Effects


Feature	First-Generation Antihistamines	Second-Generation Antihistamines
Common Examples	Diphenhydramine (Benadryl), Chlorpheniramine	Cetirizine (Zyrtec), Loratadine (Claritin), Fexofenadine (Allegra)
Likelihood of Dry Mouth/Sore Throat	High. Significant anticholinergic effects lead to reduced saliva production.	Low to Moderate. More selective action means less frequent anticholinergic effects.
Drowsiness	High. Readily cross the blood-brain barrier.	Low. Generally non-drowsy when taken as directed.
Duration of Action	Typically shorter, requiring more frequent dosing.	Longer-acting, often lasting 24 hours.
Primary Use	Allergic reactions, insomnia, motion sickness.	Daily allergy symptom management.

What to do if your antihistamine causes a sore throat

If you find yourself with a sore throat after taking your allergy medication, several strategies can help manage the discomfort:

Stay Hydrated: Drinking plenty of water is the most effective remedy. It helps keep your throat and mucous membranes moist, directly counteracting the drying effect of the medication.
Use Throat Lozenges or Sprays: Sugar-free lozenges, hard candy, or oral sprays can stimulate saliva production and provide immediate lubrication and soothing relief.
Gargle with Salt Water: A simple saltwater gargle can help reduce swelling and irritation in the throat.
Run a Humidifier: Using a humidifier, especially in your bedroom at night, can help add moisture to the air and prevent your throat from drying out while you sleep.
Chew Sugar-Free Gum: Similar to lozenges, chewing gum can increase saliva flow and combat dry mouth.
Switch Antihistamines: If the side effect is persistent or severe, your healthcare provider may recommend switching to a different antihistamine. For example, moving from a first-generation to a second-generation option might resolve the issue.

When to see a doctor

While a sore throat from antihistamines is often a manageable side effect, it's important to know when to seek professional medical advice. You should consult a doctor if:

The sore throat is severe or worsens despite home remedies.
You develop additional symptoms like a fever, persistent cough, or significant throat swelling.
The dry mouth becomes a long-term issue. Chronic dry mouth can increase the risk of dental problems, such as cavities and gum disease.
You suspect an allergic reaction to the medication itself, rather than just a drying effect, which could cause throat swelling and difficulty breathing.

Conclusion

In summary, it is possible for antihistamines to cause a sore throat, most commonly as a result of medication-induced dry mouth. The severity of this side effect often depends on the specific type of antihistamine, with older, first-generation options having a higher likelihood of causing dryness. By staying well-hydrated and using home remedies like throat lozenges and humidifiers, many individuals can effectively manage this discomfort. If the problem persists or worsens, consulting a healthcare provider to explore alternative medications is the best course of action.

For more detailed information on antihistamines, a good resource is the U.S. National Library of Medicine, where you can find detailed drug information and research. National Institutes of Health (NIH) | (.gov)

Frequently Asked Questions

Antihistamines can cause a sore throat by inducing dry mouth. This occurs because the medications can block the action of acetylcholine, a neurotransmitter that helps stimulate saliva production. With less saliva, the throat's mucous membranes become dry and irritated, leading to a sore or scratchy feeling.

Older, first-generation antihistamines, such as diphenhydramine (Benadryl), are more likely to cause a sore throat and dry mouth due to their strong anticholinergic properties. Newer, second-generation antihistamines like loratadine (Claritin) and fexofenadine (Allegra) have a lower risk, but it can still occur.

Yes, while less common than with older antihistamines, both cetirizine (Zyrtec) and fexofenadine (Allegra) have documented cases where users experience a sore throat or dry mouth as a side effect. This is typically due to the drying effect on the mucous membranes.

To treat a sore throat caused by antihistamines, the most effective methods are staying well-hydrated, using throat lozenges or hard candies to stimulate saliva, gargling with salt water, and using a humidifier, especially at night.

You should not stop taking your medication without consulting a healthcare provider. They can help determine if the sore throat is from the antihistamine or another cause and can suggest alternative remedies or a different medication with fewer side effects.

In most cases, a sore throat from antihistamines is a minor, manageable side effect. However, if it is severe, persistent, or accompanied by a fever or difficulty breathing, you should seek medical attention, as it could indicate a different issue or a more serious reaction.

Yes, increasing your fluid intake can help counteract the drying effect of antihistamines. Drinking plenty of water keeps your throat and mouth moist, which helps to lubricate the tissues and prevent irritation that can lead to a sore throat.