Important Side Effects of Cetirizine: Everything You Need to Know

An orange pill bottle that reads
  • Cetirizine is a common medication used to treat allergic reactions, hives, and other similar reactive conditions.

  • The medication can cause mild side effects like drowsiness, dry mouth, and headaches. These reactions typically go away on their own as the body adjusts to the medication.

  • In rare cases, individuals may also experience gastrointestinal issues, heart palpitations, and urinary retention.

  • Certain people should use this medication with caution. Underlying health conditions, pregnancy, and age are some factors that may make individuals more sensitive to side effects.

Cetirizine is a widely used medication that provides allergy relief and treats conditions like hay fever.

While cetirizine is generally well-tolerated, there is a risk of developing side effects.

Understanding and being able to identify these side effects is important for knowing when medical attention is required.

What is Cetirizine?

Cetirizine Hydrochloride — commonly known as Cetirizine — is an antihistamine medication used to relieve allergy symptoms and conditions like seasonal allergic rhinitis, hay fever or hives.

It works by blocking the effects of histamine — a substance in the body that causes allergy symptoms, like a runny nose and itchy eyes.

This medication is available over-the-counter (OTC) in various forms, including oral tablets, chewable pills, and syrups.

Common Side Effects of Cetirizine

Although cetirizine is generally well-tolerated, it may also cause adverse effects. These reactions are usually mild and tend to resolve without medical treatment.

Drowsiness and sedation

Cetirizine typically has a less intense sedative effect compared to other antihistamines. However, it can still cause drowsiness in some individuals.

It’s important to be mindful of the activities you engage in after taking cetirizine in the event that it causes sedation. Avoid things that require alertness, such as driving and operating machinery.

This side effect is more likely to occur when cetirizine is taken with other sedatives or at a high dose.

If you’ve taken cetirizine, do not drink alcohol or use any substances that could worsen the drowsiness caused by the medication.

In the event that you have taken substances and cetirizine together, seek emergency medical care or call the nearest poison control center for help.

Key Point: When is Drowsiness Serious?

Drowsiness caused by cetirizine is generally mild, but there are situations when it can be more serious.

If drowsiness significantly impairs your ability to perform daily activities — such as driving — or if you experience excessive sleepiness, seek medical attention immediately.

You should also consult your doctor if you experience confusion or difficulty staying awake.

These are serious symptoms that may indicate a severe adverse reaction to the medication or an underlying medical condition that requires a professional evaluation.

Woman sitting in front of a computer and yawning.

Dry mouth and throat

This medication can reduce saliva, leading to a sensation of dryness in the mouth and throat.

Although these sensations might be uncomfortable, the effect is generally mild and temporary. Increasing your fluid intake can help treat this symptom.

Headache and dizziness

Some people may experience headaches and dizziness. These symptoms will usually subside as the body gets used to the medication.

If your headaches and dizziness persist, schedule an appointment with your doctor as soon as possible.

Key Point: How Quickly Do Side Effects Develop?

The time it takes for side effects to develop varies from person to person. In most cases, you may start to experience side effects within the first few hours of taking cetirizine.

Some side effects — like gastrointestinal issues — may take a bit longer to appear and can develop over the course of several days or weeks.

Less Common Side Effects

Cetirizine may also cause less common side effects that only a small number of individuals will experience.

However, it’s important to be aware of these effects to know if you need to talk to your doctor or not.

Gastrointestinal problems

Although it’s a rare occurrence, cetirizine can occasionally cause gastrointestinal issues — such as an upset stomach, nausea, or diarrhea.

These side effects might be mild and temporary, but it’s important to seek medical attention if your gastrointestinal issues persist.

Close up of a shoulder with a rash on it being scratched.

Allergic reactions

Serious allergic reactions to cetirizine are uncommon, but they can occur if the body has a negative reaction to the histamine-1 receptors in the medication. Symptoms may include:

  • Rash

  • Itching

  • Swelling of the face, lips, tongue, and throat

  • Breathing difficulties

  • Wheezing

If you experience any signs of an allergic reaction, you should get emergency medical treatment, as this may be life-threatening if left untreated.

Urinary retention

In some cases, cetirizine may affect bladder function and result in urination difficulties and retention.

This is due to the impact of antihistamines on specific receptors in the body, which can act as muscle relaxants for the bladder.

When this happens, you may experience a delay in urinating or difficulty emptying the bladder.

It’s important to be aware of this side effect, as prolonged retention can lead to other complications like urinary tract infections (UTIs).

You should consult your doctor if you experience any signs of urinary retention or difficulties passing urine.

Increased heart rate or palpitations

Although rare, some individuals may experience changes in heart rhythm or increased heart rate while taking cetirizine.

This can cause rapid, pounding, or fluttering sensations in the chest.

If you experience any unusual heart-related symptoms, seek prompt medical attention to rule out any other underlying issues.

Key Point: What are the Symptoms of an Overdose?

If you think you’ve overdosed on cetirizine, it’s important to seek emergency medical care as soon as possible. You can also contact your local poison control center for help.

Common symptoms of an overdose include feeling restless and nervous, followed by a sensation of extreme drowsiness.

Leaving these symptoms and a potential overdose untreated could lead to fatalities.

Although this is rare, it’s still important to be aware of the signs to prevent anything serious from happening.

You can avoid overdosing by taking the medication exactly as instructed by your doctor. If you discover you have a missed dose, you can skip it without any serious risk. Do not take an extra tablet with the next dose, as this can increase your risk of overdosing.

Precautions and Special Populations

When considering the use of cetirizine, certain precautions and considerations should be taken into account.

This mainly includes certain groups of people that should exercise caution when using the medication.

Pregnancy and breastfeeding

While cetirizine is generally considered safe to use when pregnant or breastfeeding, it’s recommended to speak to your doctor about it first.

They can evaluate the potential benefits and risks based on your individual circumstances.

Your doctor can also recommend alternative medications that won’t affect the baby or potentially contaminate the breast milk.

Elderly individuals

Elderly individuals may be more susceptible to adverse reactions to cetirizine, especially dizziness and drowsiness.

To combat this, start with a lower dosage and closely monitor your response to the medication. It’s also advised that all medical and lab appointments must be kept during this time.

Healthcare professionals may also adjust the dosage if the person has an underlying condition or they need to take other medications that may interact with cetirizine.

Individuals with pre-existing conditions

If you have any pre-existing medical conditions, it’s essential to inform your doctor before taking cetirizine.

Certain conditions — such as liver or kidney disease — may require dose adjustments while using the medication.

Individuals with a history of heart disease should also be careful when using cetirizine because the medication can cause cardiovascular difficulties.

Possible drug interactions

Cetirizine can potentially interact with other medications, including other nonprescription drugs and herbal supplements.

Medications like sedatives and tranquilizers may also increase the risk of drowsiness and other nervous system effects when taken with cetirizine.

Before using cetirizine, inform your doctor about all the medication you’re currently taking.

They can recommend the appropriate precautions and make any necessary dosage adjustments.

Who shouldn’t take cetirizine?

Most adults can safely use cetirizine. It’s important to note that this medication should only be administered to children under strict medical supervision.

The following guidelines also apply to children taking cetirizine:

  • Children over the age of 1 can take cetirizine liquid if it’s been prescribed by a doctor.

  • Children over the age of 2 can take OTC or prescribed cetirizine liquid.

  • Children aged six and over can take OTC cetirizine capsules and liquid.

  • Children aged 12 and over can take cetirizine tablets, capsules, and liquid up to 10 mg.

There are a few other groups of people who should follow specific guidelines when it comes to antihistamines. Generally, cetirizine is not recommended if you:

  • Have had an allergic reaction to this or any other medication

  • Have an allergy to food additives

  • Have an allergy to peanuts or soy, as some brands of cetirizine may contain traces of these ingredients

  • Have kidney or liver disease

  • Have a urinary condition

  • Have epilepsy or any other condition that puts you at risk of having seizures

  • Are scheduled to have an allergy test

Tips for Minimizing Cetirizine Side Effects

While cetirizine is generally well-tolerated, there are some steps you can take to minimize the potential side effects.

This also ensures a more comfortable experience when using the medication. Here are a few things you can do:

  • Take the medicine as directed: Follow the recommended dosage and frequency as prescribed or indicated on the packaging. You should also avoid taking more than the recommended dose because it will not necessarily provide additional benefits.

  • Stay hydrated: Cetirizine can cause dryness in the mouth and throat. Ensure that you stay adequately hydrated by drinking plenty of fluids throughout the day. Sipping water or sugar-free beverages can help alleviate dryness and provide relief.

  • Consider timing with meals: Taking cetirizine with or without food is generally acceptable. However, if you experience any stomach upset or gastrointestinal issues, taking the medication with a meal may help.

  • Communicate with your doctor: If you have any concerns or questions or experience unusual side effects while taking cetirizine, tell your doctor about it. They can provide personalized advice or suggest alternative treatments if necessary.

Where Can You Learn More About Cetirizine and Similar Drugs?

If you’re concerned about your reaction to cetirizine or want to know more about the medication before using it, LifeMD can help.

Make an appointment with a licensed medical professional to determine if cetirizine is right for you.

Payel Gupta, MD, FACAAI

Dr. Gupta holds certifications from the American Board of Allergy and Immunology, American Board of Internal Medicine, and American Board of Pediatrics. With a deep interest in global health, she’s volunteered her clinical skills across many continents.

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This article is intended for informational purposes only and should not be considered medical advice. Consult a healthcare professional or call a doctor in the case of a medical emergency.

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