What Xyzal is
Xyzal is the brand name for levocetirizine, a second-generation antihistamine. It blocks histamine at H1 receptors, which calms sneezing, itching and a runny nose. The item we link to is Xyzal 24 Hour, levocetirizine dihydrochloride 5 mg tablets, 90 count.
Levocetirizine is the active half of cetirizine, the drug in Zyrtec. Cetirizine is a mix of two mirror-image forms of one molecule, and levocetirizine is the form that does the work. That's why Xyzal's dose is 5 mg rather than 10 mg.
Dosing follows the label and depends on age. It's taken once daily, in the evening. Adults and children 12 and up take one 5 mg tablet. Children 6 to 11 take a smaller dose, half a tablet. Adults 65 and older, and children under 6, should ask a clinician first. Never take more than the labeled dose in 24 hours.
How well it works
A 2026 network meta-analysis for the ARIA guideline panel found that the major second-generation antihistamines improve allergic rhinitis symptoms. Most differences between them were small PMID: 41707943. A separate network meta-analysis of 18 randomized trials ranked levocetirizine 5 mg among the top options for sneezing and nasal itching PMID: 37271114.
For year-round allergies, a randomized, placebo-controlled trial in 306 children aged 6 to 12 with perennial allergic rhinitis found that levocetirizine 5 mg improved symptoms and quality of life over four weeks. Side effects were no more common than with placebo PMID: 16136768. That trial used 5 mg; the US label dose for children 6 to 11 is lower, so follow the label. Perennial allergies are usually driven by dust mites, pets or mold.
Most people notice relief within about an hour, and one evening dose covers 24 hours. That makes it a reasonable fit if your symptoms are worst overnight or when you wake up.
What it treats well: sneezing, runny nose, and itchy nose, eyes and throat.
What it doesn't treat well: a blocked, stuffy nose. Steroid nasal sprays such as Flonase relieve congestion better than antihistamine pills PMID: 9848901.
Drowsiness and other side effects
Xyzal can make you drowsy. It's closely related to cetirizine, which causes sedation more often than fexofenadine or loratadine PMID: 10784544. The label's evening dosing is meant to put any sleepiness at bedtime.
Practical tips:
- Take it in the evening, as the label directs.
- Avoid alcohol, sleep aids and other sedatives while taking it.
- See how it affects you before driving the next morning.
- Ask a clinician first if you have kidney disease, or are pregnant or breastfeeding.
- Don't use it if you've had an allergic reaction to cetirizine or levocetirizine.
- The FDA has warned about rare cases of severe itching after stopping cetirizine or levocetirizine taken daily for months. If you've used it long-term, talk to a clinician before stopping.
Xyzal vs. generic cetirizine
This is the real decision. Both drugs work the same way, and both can cause drowsiness. Our estimate for Xyzal is $18–24 a month. Generic cetirizine runs about $5–8. Generic levocetirizine also exists and usually costs less than the brand.
If cetirizine already controls your symptoms, there's little reason to switch. Xyzal makes more sense if you prefer evening dosing and want levocetirizine specifically, or if a clinician suggested it.
Who should buy it
Buy Xyzal if your symptoms are worst at night or on waking, you have year-round allergies to dust mites or pets, and you're fine with an evening pill that may cause drowsiness.
Buy generic cetirizine instead if it already works for you. It's a close relative for much less.
Choose Allegra if you need a non-drowsy daytime pill. Add Flonase or Nasacort if congestion is your main problem.
See how it compares with the other options in our Best Allergy Medicines roundup.