Xyzal Allergy 24HR Side Effects

Generic name: levocetirizine

Medically reviewed by Drugs.com. Last updated on Jan 27, 2025.

Note: This document provides detailed information about Xyzal Allergy 24HR Side Effects associated with levocetirizine. Some dosage forms listed on this page may not apply specifically to the brand name Xyzal Allergy 24HR.

Applies to levocetirizine: oral solution, oral tablet.

Precautions

It is very important that your doctor check your or your child's progress to make sure this medicine is working properly. Urine tests may be needed to check for unwanted effects.

If your symptoms do not improve within a few days or if they become worse, check with your doctor.

This medicine may cause incomplete emptying of the bladder (urinary retention). Check with your doctor right away if you have a decrease in the frequency of urination or urine volume, difficulty in passing urine (dribbling), or painful urination.

This medicine may make you tired or drowsy. Do not drive or do anything else that could be dangerous until you know how this medicine affects you.

Check with your doctor before using this medicine with alcohol or other medicines that affect the central nervous system (CNS). The use of alcohol or other medicines that affect the CNS with levocetirizine (the active ingredient contained in Xyzal Allergy 24HR) may worsen the side effects of this medicine, such as dizziness, poor concentration, drowsiness, unusual dreams, and trouble with sleeping. Some examples of medicines that affect the CNS are antihistamines or medicine for allergies or colds, sedatives, tranquilizers, or sleeping medicines, medicine for depression, medicine for anxiety, prescription pain medicine or narcotics, medicine for attention deficit and hyperactivity disorder, medicine for seizures or barbiturates, muscle relaxants, or anesthetics, including some dental anesthetics.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or non-prescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

Common side effects of Xyzal Allergy 24HR

Some side effects of levocetirizine may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

Serious side effects of Xyzal Allergy 24HR

Along with its needed effects, levocetirizine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking levocetirizine:

For healthcare professionals

Applies to levocetirizine: oral solution, oral tablet.

General adverse events

The most frequently reported side effects were: somnolence, nasopharyngitis, fatigue, dry mouth, and pharyngitis (in 12 years and older); pyrexia, somnolence, cough, and epistaxis (in patients 6 to 12 years); pyrexia, diarrhea, vomiting, and otitis media (in patients 1 to 5 years); diarrhea and constipation (in patients 6 to 11 months).^[Ref]

Nervous system

• Common (1% to 10%): Somnolence, dizziness, headache
• Uncommon (0.1% to 1%): Paresthesia, syncope
• Rare (0.01% to 0.1%): Convulsion, movement disorder
• Very rare (less than 0.01%): Dysgeusia, tremor, dystonia, dyskinesia
• Frequency not reported: Orofacial dyskinesia, myoclonus, extrapyramidal symptoms
• Postmarketing reports: Febrile seizure^[Ref]

Ocular

• Very rare (less than 0.01%): Accommodation disorder, vision blurred, oculogyration
• Postmarketing reports: Visual disturbance^[Ref]

Respiratory

• Common (1% to 10%): Nasopharyngitis, pharyngitis, cough, epistaxis, rhinitis
• Postmarketing reports: Dyspnea^[Ref]

Gastrointestinal

• Common (1% to 10%): Dry mouth, diarrhea, vomiting, constipation, abdominal pain
• Postmarketing reports: Nausea^[Ref]

Other

• Common (1% to 10%): Fatigue, pyrexia, otitis media
• Uncommon (0.1% to 1%): Weight increased, asthenia, malaise
• Rare (less than 0.1%): Edema
• Frequency not reported: Stillbirth
• Postmarketing reports: Vertigo^[Ref]

Psychiatric

• Uncommon (0.1% to 1%): Agitation
• Rare (0.01% to 0.1%): Aggression, confusion, depression, hallucination, insomnia
• Very rare (less than 0.01%): Tic, enuresis
• Postmarketing reports: Suicidal ideation, nightmare^[Ref]

Genitourinary

• Very rare (less than 0.01%): Dysuria
• Postmarketing reports: Urinary retention^[Ref]

Cardiovascular

• Rare (less than 0.1%): Tachycardia
• Frequency not reported: Severe hypotension
• Postmarketing reports: Palpitation^[Ref]

Dermatologic

• Uncommon (0.1% to 1%): Pruritus, rash
• Rare (0.01% to 0.1%): Urticaria
• Very rare (less than 0.01%): Angioedema, fixed drug eruption
• Frequency not reported: Acute generalized exanthematous pustulosis^[Ref]

Hepatic

• Rare (less than 0.1%): Hepatic function abnormal, transaminases increased, bilirubin increased
• Frequency not reported: Cholestasis
• Postmarketing reports: Hepatitis^[Ref]

Hematologic

• Very rare (less than 0.01%): Thrombocytopenia^[Ref]

Immunologic

• Rare (0.01% to 0.1%): Hypersensitivity
• Very rare (less than 0.01%): Anaphylactic shock^[Ref]

Renal

• Frequency not reported: Glomerulonephritis^[Ref]

Metabolic

• Postmarketing reports: Appetite increased^[Ref]

Musculoskeletal

• Postmarketing reports: Myalgia, arthralgia^[Ref]

See also:

Frequently asked questions

• Is Xyzal available over-the-counter?

Further information

Xyzal Allergy 24HR side effects can vary depending on the individual. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Note: Medication side effects may be underreported. If you are experiencing side effects that are not listed, submit a report to the FDA by following this guide.

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