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Zafirlukast Side Effects

Medically reviewed by Last updated on Sep 18, 2022.

Applies to zafirlukast: oral tablet.

Serious side effects of Zafirlukast

Along with its needed effects, zafirlukast 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 zafirlukast:

Less common

  • Cough or hoarseness
  • fever or chills
  • lower back or side pain
  • pain
  • painful or difficult urination


  • Abdominal or stomach pain
  • clay-colored stools
  • dark urine
  • diarrhea
  • dizziness
  • headache
  • itching
  • loss of appetite
  • nausea
  • rash
  • unpleasant breath odor
  • unusual tiredness or weakness
  • vomiting of blood
  • yellow eyes or skin

Incidence not known

  • Attack, assault, or force
  • attempts at killing oneself
  • discouragement
  • dry mouth
  • fear or nervousness
  • feeling sad or empty
  • fever with or without chills
  • general feeling of tiredness or weakness
  • hyperventilation
  • irregular heartbeats
  • irritability
  • lack of appetite
  • large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
  • loss of interest or pleasure
  • restlessness
  • seeing, hearing, or feeling things that are not there
  • shakiness in the legs, arms, hands, or feet
  • shortness of breath
  • sleeplessness
  • sore throat
  • sores, ulcers, or white spots on the lips or in the mouth
  • tiredness
  • trembling or shaking of the hands or feet
  • trouble with concentrating
  • trouble with sleeping
  • unable to sleep
  • unusual bleeding or bruising

Other side effects of Zafirlukast

Some side effects of zafirlukast 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:

Less common

  • Acid or sour stomach
  • back pain
  • belching
  • difficulty with moving
  • heartburn
  • indigestion
  • joint pain
  • lack or loss of strength
  • muscle aching or cramping
  • muscle pains or stiffness
  • stomach discomfort or upset
  • swollen joints
  • vomiting

Incidence not known

  • Hives or welts
  • redness of the skin

For Healthcare Professionals

Applies to zafirlukast: oral tablet.


The most commons adverse effects may be associated with headache or gastrointestinal disturbances. These symptoms are usually mild.[Ref]

Nervous system

Very common (10% or more): Headache (up to 12.9%)

Common (1% to 10%): Dizziness (1.6%)

Frequency not reported: Neuropathy, neuropsychiatric events[Ref]


Common (1% to 10%): Nausea (up to 3.1%), diarrhea (up to 2.8%), abdominal pain (up to 2.8%), vomiting (up to 1.5%), dyspepsia (1.3%)[Ref]


In most of the postmarketing reports, the patient's symptoms abated and the liver enzymes returned to normal or near normal after stopping this drug.[Ref]

Common (1% to 10%): SGPT elevation (1.5%), AST (1.4%)

Rare (less than 0.1%): Hyperbilirubinemia without other elevated liver function tests; fulminant hepatitis or progressed to hepatic failure, liver transplantation and death

Postmarketing reports: Symptomatic hepatitis (with or without hyperbilirubinemia) without other attributable cause; hepatic dysfunction[Ref]


Common (1% to 10%): Myalgia (1.6%), back pain (1.5%)

Frequency not reported: Arthralgia[Ref]


Common (1% to 10%): Generalized pain (1.9%), asthenia (up to 1.8%), accidental injury (1.6%), fever (1.4%)

Rare (less than 0.1%): Increased theophylline levels with or without clinical signs or symptoms of theophylline toxicity when this drug was added to an existing theophylline regime.

Frequency not reported: Edema, malaise[Ref]


Common (1% to 10%): Respiratory tract infection (3.5%)[Ref]

Infections were usually mild or moderate, predominantly affecting the respiratory tract and not necessitating withdrawal from the therapy.

In clinical trials, an increased proportion of patients over the age of 55 years reported these infections. Infections occurred equally in both sexes and were associated with coadministration of inhaled corticosteroids.[Ref]


Rare (less than 0.1%): Bleeding disorders including menorrhagia, thrombocytopenia[Ref]


Rare (less than 0.1%): Alopecia

Frequency not reported: Bruising, pruritus[Ref]


Rare (0.01% to 0.1%): Granulomatosis

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


Systemic eosinophilia may also involve various body systems including vasculitic rash, worsening pulmonary symptoms, cardiac complications or neuropathy.[Ref]

Rare (less than 0.1%): Systemic eosinophilia, eosinophilic pneumonia, or clinical features of vasculitis consistent with Churg-Strauss syndrome[Ref]


Frequency not reported: Urticaria, angioedema, rashes (with or without blistering)[Ref]


Frequency not reported: Insomnia, depression[Ref]


1. Product Information. Accolate (zafirlukast). Astra-Zeneca Pharmaceuticals. 2001.

2. Cerner Multum, Inc. UK Summary of Product Characteristics.

3. Cerner Multum, Inc. Australian Product Information.

4. Spector SL, Smith LJ, Glass M. Effects of 6 weeks of therapy with oral doses of ICI 204,219, a leukotriene D4 receptor antagonist, in subjects with bronchial asthma. ACCOLATE Asthma Trialists Group. Am J Respir Crit Care Med. 1994;150:618-23.

5. Smith LJ, Geller S, Ebright L, Glass M, Thyrum PT. Inhibition of leukotriene D4-induced bronchoconstriction in normal subjects by the oral LTD4 receptor antagonist ICI 204,219. Am Rev Respir Dis. 1990;141:988-92.

6. Findlay SR, Barden JM, Easley CB, Glass M. Effect of the oral leukotriene antagonist, ICI 204,219, on antigen- induced bronchoconstriction in subjects with asthma. J Allergy Clin Immunol. 1992;89:1040-5.

7. Spector SL. Leukotriene inhibitors and antagonists in asthma. Ann Allergy Asthma Immunol. 1995;75:463-70,473-4.

8. Kelloway JS. Zafirlukast: the first leukotriente-receptor antagonist approved for the treatment of asthma. Ann Pharmacother. 1997;31:1012-21.

9. Torres M, Reddy KR. Severe liver injury. Ann Intern Med. 2001;135:550.

10. Danese S, De Vitis I, Gasbarrini A. Severe Liver Injury Associated with Zafirlukast. Ann Intern Med. 2001;135:930.

11. Katz RS, Papernik M. Zafirlukast and Churg-Strauss syndrome. JAMA. 1998;279:1949.

12. Honsinger RW. Zafirlukast and Churg-Strauss syndrome. JAMA. 1998;279:1949.

13. Churg J, Churg A. Zafirlukast and Churg-Strauss syndrome. JAMA. 1998;279:1949-50.

14. Wechsler ME, Drazen JM. Zafirlukast and Churg-Strauss syndrome - Reply. JAMA. 1998;279:1950.

15. Knoell DL, Lucas J, Allen JN. Churg-Strauss syndrome associated with zafirlukast. Chest. 1998;114:332-4.

16. Wechsler ME, Garpestad E, Rlier SR, et al. Pulmonary infiltrates, eosinophilia, and cardiomyopathy following corticosteroid withdrawal in patients with asthma receiving zafirlukast. JAMA. 1998;279:455-7.

17. Green RL, Vayonis AG. Churg-Strauss syndrome after zafirlukast in two patients not receiving systemic steroid treatment. Lancet. 1999;353:725-6.

18. Finkel TH, Hunter DJ, Paisley JE, Finkel RS, Larsen GL. Drug-induced lupus in a child after treatment with zafirlukast (Accolate). J Allerg Clin Immunol. 1999;103:533-4.

19. Wechsler M, Drazen JM. Churg-Strauss syndome. Lancet. 1999;353:1999.

20. Wechsler ME, Drazen JM. Zafirlukast and Churg-Strauss syndrome. Chest. 1999;116:266-7.

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.