Cetirizine vs Levocetirizine: Uses, Differences, Side Effects and Which Is Better?

Allergies can cause sneezing, a runny nose, itchy eyes, skin rashes and constant itching. Two commonly used medicines for managing these symptoms are cetirizine and levocetirizine. Both belong to a group of medicines called antihistamines and help reduce allergy symptoms.

However, many people have questions about cetirizine vs levocetirizine. What is the difference between these medicines? Is levocetirizine better than cetirizine? Which medicine causes less drowsiness, and can they be taken together?

In this article, we will explain the difference between cetirizine and levocetirizine, including their uses, benefits, dosage, side effects and safety precautions, in simple language.

Cetirizine is an antihistamine medicine used to relieve symptoms caused by allergies. It works by blocking histamine, a chemical released by the body during an allergic reaction.

When histamine is released, it can cause sneezing, a runny nose, itchy eyes and skin rashes. Cetirizine helps reduce these symptoms and makes you feel more comfortable.

Cetirizine is commonly used for:

• Allergic rhinitis: Helps relieve sneezing, a runny nose and nasal itching caused by allergies.
• Hay fever: Reduces allergy symptoms triggered by pollen and other allergens.
• Watery and itchy eyes: Helps relieve eye irritation associated with allergies.
• Skin allergies: Helps manage itching caused by certain allergic skin conditions.
• Hives (urticaria): Helps reduce itchy, raised bumps on the skin.
• Dust and pet allergies: Helps relieve symptoms triggered by dust mites, animal dander and other allergens.

Cetirizine can help control allergy symptoms, but it does not cure the underlying allergy.

Levocetirizine is an antihistamine used to treat allergy symptoms. It belongs to the same group of medicines as cetirizine and works by blocking the effects of histamine in the body.

Levocetirizine is the active R-enantiomer of cetirizine. In simple terms, cetirizine contains two mirror-image forms of the molecule, while levocetirizine contains one of these forms.

Like cetirizine, levocetirizine helps reduce sneezing, a runny nose, itchy eyes and skin itching caused by allergies.

Levocetirizine is commonly used to manage:

• Allergic rhinitis: Helps relieve sneezing, nasal itching and a runny nose.
• Seasonal allergies: Helps control symptoms caused by pollen and other seasonal allergens.=
• Perennial allergies: Helps manage allergies that occur throughout the year.
• Skin allergies: Helps reduce itching associated with certain allergic conditions.
• Hives (urticaria): Helps relieve itching and raised skin rashes.
• Eye allergy symptoms: Helps reduce itchy and watery eyes associated with allergies.

The exact approved uses and suitable dose may vary according to the patient's age, medical condition and the product being used.

Cetirizine and levocetirizine work in a similar way, but they differ in their chemical composition and usual doses.

Here are the main differences between cetirizine and levocetirizine.

1. Active Ingredient

Cetirizine contains a mixture of two mirror-image forms of the same molecule. Levocetirizine contains only the active R-enantiomer of cetirizine.

This difference explains why the two medicines have different usual doses. However, it does not automatically mean that levocetirizine is more effective for every person.

2. Uses

Both cetirizine and levocetirizine are used to manage common allergy symptoms.

They can help with:

• Sneezing and a runny nose
• Nasal itching
• Itchy and watery eyes
• Skin itching
• Hives and allergic rashes

Neither medicine is suitable for every type of allergy or every patient. The best choice depends on the symptoms, medical history and advice of a healthcare professional.

3. Dosage

The usual adult dose of cetirizine is 10 mg once daily, while the usual adult dose of levocetirizine is 5 mg once daily.

These are common adult doses, not instructions for everyone. People with kidney problems and some older adults may require a lower dose or a different dosing schedule. Children's doses depend on their age, the formulation and the specific product instructions.

Important: Do not increase the dose or switch between these medicines without checking with a doctor or pharmacist.

4. Drowsiness

Both cetirizine and levocetirizine can cause sleepiness or tiredness.

Cetirizine is often described as a non-drowsy antihistamine, but it can still make some people sleepy. Levocetirizine can also cause drowsiness, and it is not guaranteed to cause less sleepiness than cetirizine.

The effect varies from person to person. Avoid driving or operating machinery until you know how the medicine affects you.

5. How Quickly They Work

Both medicines can start relieving allergy symptoms within about an hour in many people. The exact time may vary depending on the person and the symptoms being treated.

Neither medicine necessarily works better for everyone, and the speed of relief does not determine which one is the best choice.

6. Duration of Action

Both cetirizine and levocetirizine are commonly taken once daily because their effects can last for about 24 hours in many people.

However, the duration of relief may vary. Follow the prescribed schedule instead of taking another dose when symptoms return.

There is no single answer to whether cetirizine or levocetirizine is better. Both medicines can provide effective relief from common allergy symptoms.

The better option depends on how well the medicine controls your symptoms, whether you experience side effects and whether you have any medical conditions that affect its use.

Cetirizine may be suitable when:

• You need relief from sneezing and a runny nose caused by allergies.
• You have itching or hives associated with an allergic condition.
• Your doctor recommends cetirizine based on your symptoms and medical history.

However, if cetirizine makes you sleepy or causes other troublesome side effects, speak to your doctor about suitable alternatives.

Levocetirizine may be suitable when:

• You need relief from common allergy symptoms.
• You have allergic rhinitis or certain itchy skin conditions.
• Your doctor recommends it based on your response to other allergy medicines.

Levocetirizine is a closely related medicine, so it may not eliminate side effects experienced with cetirizine.

The bottom line: Cetirizine and levocetirizine are both useful allergy medicines. The choice should depend on your symptoms, response to treatment, medical history and the advice of your healthcare professional rather than the assumption that one is always stronger or better.

Both medicines can help control different types of allergy symptoms.

For Sneezing and a Runny Nose

Cetirizine and levocetirizine can both help relieve sneezing, nasal itching and a runny nose caused by allergic rhinitis.

If you have persistent nasal blockage, you may need a different treatment or an additional medicine recommended by your doctor.

For Skin Allergies and Itching

Both medicines can help reduce itching caused by certain allergic skin conditions.

They are also used to manage hives, which appear as raised, itchy bumps on the skin.

However, not every skin rash is caused by an allergy. If a rash is painful, blistered, unusual or persistent, seek medical advice instead of treating it with an antihistamine alone.

For Seasonal Allergies

Seasonal allergies may cause sneezing, a runny nose and itchy eyes during certain times of the year.

Both cetirizine and levocetirizine can help manage these symptoms. Your doctor can help you choose the appropriate medicine based on your symptoms and treatment response.

Like other medicines, cetirizine and levocetirizine can cause side effects. Many people tolerate them well, but some may experience unwanted effects.

Common Side Effects of Cetirizine

Common side effects may include:

• Sleepiness or drowsiness
• Tiredness
• Dry mouth
• Headache
• Dizziness
• Nausea in some people

Common Side Effects of Levocetirizine

Common side effects may include:

• Sleepiness or drowsiness
• Tiredness
• Dry mouth
• Headache in some people

The side effects can overlap because both medicines work in a similar way. The type and severity of side effects vary from person to person.

How to Reduce the Risk of Side Effects

Follow these precautions while taking either medicine:

• Take the medicine according to your doctor's instructions.
• Avoid alcohol because it may increase drowsiness.
• Do not drive if you feel sleepy or dizzy.
• Tell your doctor about other medicines you are taking.
• Inform your doctor if you have kidney problems or other significant medical conditions.

Seek urgent medical attention if you develop difficulty breathing, swelling of the tongue or throat, or other signs of a severe allergic reaction.

Long-term use warning: The US Food and Drug Administration has warned about rare cases of severe itching after stopping cetirizine or levocetirizine following daily use for several months or years. If you take either medicine regularly for a long period, discuss how to stop it safely with your healthcare professional.

The correct dosage depends on the person's age, medical condition, kidney function and the formulation prescribed.

Cetirizine Dosage

For many adults, the usual dose is 10 mg once daily. Some people may need a lower dose based on their medical condition or the advice of their doctor.

Cetirizine is available in different formulations, including tablets and oral liquids.

Levocetirizine Dosage

For many adults, the usual dose is 5 mg once daily. A lower dose may be needed for people with kidney problems.

Levocetirizine is available in tablet and oral liquid formulations, depending on the product.

Important Dosage Precautions

• Do not take more than the recommended dose.
• Do not take cetirizine and levocetirizine together unless specifically directed by a healthcare professional.
• Check the label carefully before taking a combination allergy medicine.
• Consult a doctor before giving either medicine to a child.
• If you miss a dose, follow the product instructions or ask a pharmacist. Do not take a double dose to make up for a missed one.

No, you should not take cetirizine and levocetirizine together unless your doctor specifically instructs you to do so.

Both medicines act on histamine and have similar effects. Taking them together may increase the risk of side effects, including drowsiness and tiredness, without providing additional benefit.

If one medicine is not relieving your symptoms, consult your doctor instead of combining the two medicines or increasing the dose yourself.

Both medicines may be prescribed for children with certain allergy symptoms. However, the appropriate medicine and dose depend on the child's age, weight where relevant, medical condition and the specific product.

Parents and caregivers should:

• Use only an age-appropriate formulation.
• Follow the prescribed dose carefully.
• Measure liquid medicine using the supplied measuring device.
• Avoid giving adult doses to children.
• Seek medical advice if symptoms persist or worsen.

Do not give these medicines to a young child without checking the product's age restrictions and consulting a healthcare professional.

Before using cetirizine or levocetirizine, speak to your doctor if you:

• Have kidney disease or reduced kidney function.
• Are pregnant, planning a pregnancy or breastfeeding.
• Take sleeping pills, sedatives or other medicines that cause drowsiness.
• Have previously experienced a reaction to either medicine.
• Need to take an antihistamine regularly for several months.

Your doctor can assess whether the medicine is appropriate and recommend a suitable dose.

Cetirizine and levocetirizine are antihistamine medicines that help relieve allergy symptoms such as sneezing, a runny nose, itchy eyes and skin itching. Both work by blocking the effects of histamine, but they differ in their chemical composition and usual dosage.

The main difference between cetirizine and levocetirizine is that levocetirizine contains only the active R-enantiomer of cetirizine. However, neither medicine is automatically better for everyone, and both can cause drowsiness.

Choose an allergy medicine based on your symptoms, medical history and healthcare professional's advice. Do not take both medicines together or change your dose without medical guidance.