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Xyzal Allergy 24HR Side Effects

Generic Name: levocetirizine

Note: This document contains side effect information about levocetirizine. Some of the dosage forms listed on this page may not apply to the brand name Xyzal Allergy 24HR.

In Summary

More frequent side effects include: drowsiness, fatigue, and nasopharyngitis. See below for a comprehensive list of adverse effects.

For the Consumer

Applies to levocetirizine: oral solution, oral tablet

Along with its needed effects, levocetirizine (the active ingredient contained in Xyzal Allergy 24HR) 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:

Less common Incidence not known
  • Anxiety
  • attack, assault, or force
  • blurred or loss of vision
  • cough
  • dark urine
  • decrease in the frequency of urination
  • decrease in urine volume
  • difficult or labored breathing
  • difficulty in passing urine (dribbling)
  • difficulty with swallowing
  • disturbed color perception
  • dizziness
  • double vision
  • dry mouth
  • fast, irregular, pounding, or racing heartbeat or pulse
  • general tiredness and weakness
  • halos around lights
  • hives or welts
  • hyperventilation
  • irritability
  • itching skin
  • joint or muscle pain
  • large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
  • light-colored stools
  • nausea and vomiting
  • nervousness
  • night blindness
  • overbright appearance of lights
  • painful urination
  • puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
  • redness of the skin
  • restlessness
  • seizures
  • shaking
  • skin rash
  • tightness in the chest
  • trouble with sleeping
  • tunnel vision
  • upper right abdominal or stomach pain
  • yellow eyes and skin

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:

More common Less common
  • Body aches or pain
  • congestion
  • diarrhea
  • dryness or soreness of the throat
  • earache
  • hoarseness
  • redness or swelling in the ear
  • tender, swollen glands in the neck
  • voice changes

For Healthcare Professionals

Applies to levocetirizine: oral solution, oral tablet


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]


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


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


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


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]


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]


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


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


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]


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


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


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


Frequency not reported: Glomerulonephritis[Ref]


Postmarketing reports: Appetite increased[Ref]


Postmarketing reports: Myalgia, arthralgia[Ref]


1. "Product Information. Xyzal (levocetirizine)." UCB Pharma Inc, Smyrna, GA.

2. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0

Some side effects of Xyzal Allergy 24HR may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

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