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Clarinex Side Effects

Generic name: desloratadine

Medically reviewed by Last updated on Mar 11, 2023.

Note: This document contains side effect information about desloratadine. Some dosage forms listed on this page may not apply to the brand name Clarinex.


More frequent side effects include: fatigue, pharyngitis, and nausea. Continue reading for a comprehensive list of adverse effects.

Applies to desloratadine: oral tablet, oral tablet disintegrating.

Serious side effects of Clarinex

Along with its needed effects, desloratadine (the active ingredient contained in Clarinex) 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 desloratadine:


  • Anaphylaxis, such as, cough, difficulty swallowing, dizziness, fast heartbeat, hives, itching, puffiness or swelling of eyelids or around the eyes or face or lips or tongue, shortness of breath, skin rash, tightness in chest, unusual tiredness or weakness, wheezing
  • dyspnea, such as, shortness of breath, difficult or labored breathing, tightness in chest, wheezing
  • edema, such as, swelling
  • pruritus, such as, itching skin
  • rash
  • tachycardia, such as, fast, pounding, or irregular heartbeat or pulse
  • urticaria, such as, hives or welts, itching, redness of skin, skin rash.

Other side effects of Clarinex

Some side effects of desloratadine 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

  • Dizziness
  • dry mouth
  • dysmenorrhea, such as, difficult or painful menstruation
  • dyspepsia, such as, acid or sour stomach, belching, heartburn, indigestion, stomach discomfort , upset or pain,
  • fatigue, such as, unusual tiredness or weakness
  • myalgia, such as, joint pain, swollen joints, muscle aching or cramping, muscle pains or stiffness, difficulty in moving
  • pharyngitis, such as, body aches or pain, congestion, cough, dryness or soreness of throat, fever, hoarseness, runny nose, tender swollen glands in neck, trouble in swallowing, voice changes.
  • somnolence, such as, sleepiness or unusual drowsiness
  • nausea

For Healthcare Professionals

Applies to desloratadine: oral solution, oral tablet, oral tablet disintegrating.


The most commonly reported side effects included upper respiratory tract infections, diarrhea, fever, and headache.[Ref]


Very common (10% or more): Upper respiratory tract infections (up to 21.2%), coughing (up to 10.8%)

Common (1% to 10%): Bronchitis, epistaxis, rhinorrhea

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

Upper respiratory tract infections were reported in 21.2% of patients 6 to 11 months of age given oral solution formulations, and coughing was reported in 10.8% of patients 12 to 23 months of age given oral solution formulations.[Ref]


Very common (10% or more): Diarrhea (up to 19.7%)

Common (1% to 10%): Dry mouth, dyspepsia, nausea, pharyngitis, vomiting

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

In patients treated for chronic idiopathic urticaria, nausea was reported in up to 5%, pharyngitis was reported in 3%, and dyspepsia was reported in 3% of patients 12 years and older.

Diarrhea was reported in 19.1% of patients 6 to 11 months of age given oral solution formulations.[Ref]


Fever was reported in 16.9% of patients 12 to 23 months of age given oral solution formulations.

In patients treated for chronic idiopathic urticaria, fatigue was reported in up to 5% of patients 12 years and older.[Ref]

Very common (10% or more): Fever (up to 16.9%)

Common (1% to 10%): Fatigue

Frequency not reported: Asthenia[Ref]

Nervous system

Very common (10% or more): Headache (up to 14%)

Common (1% to 10%): Dizziness, somnolence

Very rare (less than 0.01%): Psychomotor hyperactivity, seizures

Postmarketing reports: Dystonia, extrapyramidal symptoms, movement disorder[Ref]

In patients treated for chronic idiopathic urticaria, headache was reported in up to 14% and dizziness was reported in 4% of patients 12 years and older.

Seizures have been reported in patients with and without seizure disorders.

Movement disorders included dystonia, extrapyramidal symptoms, and tics.[Ref]


Irritability was reported in 12.1% of patients 6 to 11 months of age given oral solution formulations.

Insomnia was reported in 2.3% of patients 6 to 23 months of age given oral syrup formulations.[Ref]

Very common (10% or more): Irritability (up to 12.1%)

Common (1% to 10%): Emotional lability, insomnia

Very rare (less than 0.01%): Hallucinations

Frequency not reported: Abnormal behavior, aggression

Postmarketing reports: Tics[Ref]


Common (1% to 10%): Erythema, rash maculopapular

Very rare (less than 0.01%): Pruritus, rash, urticaria

Frequency not reported: Photosensitivity[Ref]


Common (1% to 10%): Anorexia, appetite increased

Frequency not reported: Weight increased[Ref]


Common (1% to 10%): Parasitic infection, varicella[Ref]


Common (1% to 10%): Dysmenorrhea, urinary tract infection[Ref]


In patients treated for chronic idiopathic urticaria, myalgia was reported in up to 3%of patients 12 years and older.[Ref]

Common (1% to 10%): Myalgia[Ref]


Common (1% to 10%): Otitis media[Ref]


Very rare (less than 0.01%): Hepatitis, increased bilirubin, liver enzyme elevations

Frequency not reported: Jaundice[Ref]


Very rare (less than 0.01%): Anaphylaxis, angioedema, hypersensitivity reactions[Ref]


Very rare (less than 0.01%): Palpitations, tachycardia

Frequency not reported: QT prolongation

Postmarketing reports: Arrhythmia, bradycardia, edema[Ref]


1. "Product Information. Clarinex (desloratadine)." Schering Corporation (2002):

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

3. Cerner Multum, Inc. "Australian Product Information." O 0

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.