Xyzal for allergies: what is it and how does it work?

Mike Bohl, MD, MPH, ALM - Contributor Avatar

Written by Michael Martin 

Mike Bohl, MD, MPH, ALM - Contributor Avatar

Written by Michael Martin 

last updated: Apr 01, 2021

3 min read

If you’re one of more than 50 million Americans who suffer from seasonal allergies, chances are, you’ve probably tried your fair share of allergy medications. Whether you’ve reached for pills, drops, nasal sprays, or shots, you’ve probably noticed that some remedies are more effective than others. But with all the different types of allergy medications out there—antihistamines, corticosteroids, immunotherapy, and more—you might be wondering what kinds of potential advantages and disadvantages one particular type of medication has compared to any other. We’ve covered everything you need to know about Xyzal, how Xyzal works, what benefits it offers, and what kinds of side effects you can expect if you start using it.


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What is Xyzal?

Xyzal is the brand name for a drug called levocetirizine, which is an antihistamine. Your immune system is supposed to react to harmful intruders, but sometimes, it can react to something that isn’t harmful at all. When your body is sensitive to a specific substance like pollen, pet dander, or peanuts (called an allergen), your immune system releases chemicals called histamines (Dougherty, 2020).

Histamines are responsible for some of the signature symptoms of an allergic reaction, like a runny nose, hives, sneezing, and more. Antihistamines work by blocking the hormones, alleviating the symptoms of seasonal allergies or even preventing them altogether (NIH, 2018).

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Antihistamine medications can be both prescription-strength or available over-the-counter (OTC). They come in different forms like pills, chewable tablets, liquids, and capsules. 

The Food and Drug Administration (FDA) has approved Xyzal as a type of OTC antihistamine that’s designed to provide 24-hour relief from symptoms associated with seasonal allergies (Akhouri, 2021). These symptoms include:

  • Runny nose

  • Sneezing

  • Red or itchy eyes

  • Hives or itchy rash

Different types of allergens can trigger these symptoms in different people. Some of the most common triggers of these allergic symptoms include pollen, dust mites, pet dander, and mold, but people can experience seasonal allergies or year-round allergies to many different substances.

How does Xyzal work?

Just like other antihistamines like cetirizine (brand name Zyrtec), diphenhydramine (brand name Benadryl), and loratadine (brand name Claritin), Xyzal helps treat allergy symptoms by blocking the effects of histamines in the body. Histamines play a major role in allergic reactions and blocking them can alleviate or even prevent symptoms of hayfever altogether.Antihistamines work by preventing histamines from binding to the receptors on certain cells. But they are involved in a wide range of processes—not just immune responses. For example, they play an important role in the sleep-wake cycle which keeps us awake during the day and lets us sleep at night. Since some of these medications can disrupt this process, they’re known to cause drowsiness (Farzam, 2021). Certain antihistamines (like Benadryl) are so effective at making you drowsy that their main ingredients are often used for that purpose in over-the-counter insomnia medications. This effect is something you should be aware of when starting a new antihistamine. Drugs like Xyzal, which are part of a newer form of antihistamines called second-generation antihistamines, are sometimes preferred by healthcare providers since they are less likely to cause sedation, but they can still cause tiredness, so it’s best to always follow dosage instructions and to talk to your doctor before taking Xyzal or any other medication (Becker, 2018). Xyzal comes in the form of 5 mg breakable tablets as well as in a 2.5 mg/5 mL oral solution. Xyzal is available over-the-counter and therefore you don’t need a prescription to purchase it. You can take Xyzal with or without food. Because Xyzal may cause you to feel tired, it’s best to take it in the evening. You should also avoid driving a motor vehicle or operating machinery until you know how the medication affects you.

What are the potential side effects and risks of Xyzal?

Like all prescription and OTC medications, Xyzal may cause side effects in some people. Some of the most common side effects of Xyzal include (FDA, 2020):

  • Headache

  • Muscle aches

  • Sleepiness

  • Sore throat

  • Cough

  • Stuffy nose or runny nose

Some of the less common side effects of Xyzal include:

  • Diarrhea

  • Tender, swollen glands in the neck

  • Bloody nose

  • Fever

Xyzal carries the risk of other side effects too. These include anxiety, trouble sleeping, and vision problems. If you experience any concerning side Xyzal carries the risk of other side effects too. These include anxiety, trouble sleeping, and vision problems. If you experience any concerning side effects or are concerned about your risk of side effects, be sure to talk to a healthcare provider before taking Xyzal. Serious side effects of Xyzal include hives, rash, itching, and/or swelling of the arms, feet, ankles, or lower legs (NIH, 2016). Talk to your healthcare provider before taking Xyzal if you’re pregnant or plan to become pregnant. Don’t take Xyzal if you’re breastfeeding, and be sure to talk to your healthcare provider if you have or have ever had kidney disease, liver disease, or are on dialysis. You can also discuss the safe use of alcohol while taking Xyzal since drinking alcohol can increase the amount of drowsiness you experience.


If you have any medical questions or concerns, please talk to your healthcare provider. The articles on Health Guide are underpinned by peer-reviewed research and information drawn from medical societies and governmental agencies. However, they are not a substitute for professional medical advice, diagnosis, or treatment.

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Current version

April 01, 2021

Written by

Michael Martin

Fact checked by

Mike Bohl, MD, MPH, ALM

About the medical reviewer

Dr. Mike is a licensed physician and a former Director, Medical Content & Education at Ro.