Zafirlukast
Pronunciation: (za-FIR-loo-kast).
- Generic name
- zafirlukast
- Brand names
- Accolate
- Drug class
- Leukotriene receptor antagonist (LTRA)
Availability and supply rules vary by country
Trade names by country: Canada
Australia: · Full directory
What zafirlukast is and how it works
Uses, formulations, monitoring, and supply rules can differ by patient, product, and country. Follow the exact local product information and professional advice.
Mechanism of action: how zafirlukast works
Zafirlukast is a selective leukotriene receptor antagonist (LTRA) that blocks the action of cysteinyl leukotrienes (LTC4, LTD4, and LTE4) at the CysLT1 receptor in the airway smooth muscle and other cells. This inhibition reduces bronchoconstriction, vascular permeability, and inflammation associated with asthma. (1)
What zafirlukast is used for
Asthma prophylaxis
Asthma prophylaxis
Chronic asthma treatment
Chronic asthma treatment
Exercise-induced bronchoconstriction prevention
Exercise-induced bronchoconstriction prevention
Before taking zafirlukast
Do not take / not appropriate for
- Contraindicated in patients with known hypersensitivity to zafirlukast or severe hepatic impairment. (Contraindication)
Tell your clinician about
How to take zafirlukast
- General Instructions: Take zafirlukast exactly as prescribed by your doctor, usually twice daily. Take it on an empty stomach, at least 1 hour before or 2 hours after meals.. Adult Dosing: The typical adult dose is 20 mg taken orally twice daily.. Pediatric Dosing: For children aged 5–11 years, the usual dose is 10 mg taken orally twice daily. Safety and efficacy have not been established for children under 5 years.. Administration: Swallow the tablet whole with water. Do not crush or chew. Take at the same times each day for best results.. When To Seek Review: Do not stop taking zafirlukast without consulting your doctor, even if you feel better. Stopping suddenly may worsen asthma symptoms.. Storage: Store at room temperature (20–25°C/68–77°F), away from moisture and heat. Keep out of reach of children.
- This page does not provide a dose calculator. Dosing must follow the prescriber, pharmacist, or product label.
Procedures and treatment changes
Tell the treating team before surgery, procedures, or any medicine change. Do not alter treatment without the responsible clinician.
Missed dose
If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, contact your prescriber or pharmacist for guidance on the missed dose and resume your regular schedule. do not take an extra dose to catch up.
Overdose
In case of overdose, seek emergency medical attention or contact a poison control center immediately. Symptoms may include headache, upset stomach, or drowsiness. Supportive care is recommended as there is no specific antidote.
Side effects
Side effects and their urgency vary; report severe, persistent, or concerning symptoms to a healthcare professional.
Headache
Incidence: Reported in the clinician-authored database; frequency not established
Nausea
Incidence: Reported in the clinician-authored database; frequency not established
Diarrhea
Incidence: Reported in the clinician-authored database; frequency not established
Abdominal pain
Incidence: Reported in the clinician-authored database; frequency not established
Elevated liver enzymes
Incidence: Reported in the clinician-authored database; frequency not established
Churg-Strauss syndrome
Incidence: Reported in the clinician-authored database; frequency not established
Hypersensitivity reactions
Incidence: Reported in the clinician-authored database; frequency not established
Serious warnings
Not for use in acute asthma attacks — serious
Symptoms: Not for use in acute asthma attacks. May cause liver problems; monitor for symptoms such as jaundice. Use with caution in patients with pre-existing liver disease. May interact with warfarin and other drugs. Rarely associated with Churg-Strauss syndrome.
Action: Follow the urgency stated and seek prompt or emergency care when indicated.
Contraindications recorded in the clinician database — serious
Symptoms: Contraindications recorded in the clinician database: Contraindicated in patients with known hypersensitivity to zafirlukast or severe hepatic impairment. Use with caution in patients with mild to moderate hepatic dysfunction. The treating clinician monitors for signs of liver dysfunction and decides on treatment when significant hepatic injury is suspected.
Action: Follow the urgency stated and seek prompt or emergency care when indicated.
Interactions
| Medicine or test | Effect | Action |
|---|---|---|
| Recorded interactions | Zafirlukast may interact with warfarin (increasing bleeding risk), theophylline, erythromycin, and certain other medications. Always inform your healthcare provider about all medicines and supplements you are taking. Monitor INR closely if used with warfarin. | (1) |
Pregnancy, breastfeeding, kidney/liver function, age
Pregnancy
Zafirlukast is used during pregnancy only if clearly needed — a decision made with the prescriber (animal studies showed no teratogenicity at high doses).
Breastfeeding
Zafirlukast passes into breast milk, and the label states it should not be given to breastfeeding mothers; discuss alternatives with the prescriber.
Children
Approved for asthma in children 5 years and older (10 mg twice daily per the label); safety and effectiveness under 5 years are not established.
Kidney_impairment
No dosage adjustment is required in renal impairment.
Liver_impairment
Contraindicated in hepatic impairment, including cirrhosis; life-threatening hepatic failure has been reported — new abdominal pain, nausea, fatigue, jaundice, or flu-like symptoms need immediate contact with the physician, who decides on treatment.
Older_adults
Exposure is 2–3 times higher over 65, but the standard dose was not associated with more adverse events in trials; the prescriber weighs this.
Monitoring
Storage
Store at room temperature, 20–25°C, protected from moisture and heat, in the original container, out of reach of children.
Study the drug class: Leukotriene receptor antagonists
Professional information
Clinician-facing context only. This section does not replace current product labeling.
General
Indication: Asthma prophylaxis
Dose summary: 20 mg orally twice daily
Renal context: No dosage adjustment required in renal impairment. Contraindicated in hepatic impairment including cirrhosis. (1) (2)
Frequently asked questions
What is zafirlukast used for?
Zafirlukast is used to help prevent and control asthma symptoms. It is not a rescue medication and should not be used for sudden asthma attacks.
How does zafirlukast work?
Zafirlukast blocks leukotriene receptors in the lungs, reducing inflammation, swelling, and tightening of the airways to help prevent asthma symptoms.
Can I use zafirlukast during an asthma attack?
No, zafirlukast is not effective for treating acute asthma attacks. Always use your rescue inhaler for sudden symptoms.
What should I do if I miss a dose?
Take the missed dose as soon as you remember. If it’s almost time for your next dose, contact your prescriber or pharmacist for guidance on the missed dose and continue your regular schedule. do not take an extra dose.
Are there any serious side effects?
Serious side effects include liver problems, severe allergic reactions, and rare immune system reactions. Seek medical help if you notice yellowing of the skin or eyes, severe abdominal pain, or difficulty breathing.
Can children take zafirlukast?
Yes, zafirlukast is approved for children 5 years and older. The dose for children is typically lower than for adults.
Can I stop taking zafirlukast if I feel better?
Talk to your doctor before any change — your asthma can worsen without it, and the doctor advises whether and how to stop.
What happens if I take too much Zafirlukast?
Taking too much Zafirlukast can lead to an overdose, potentially causing symptoms such as headache, nausea, and abdominal pain. In severe cases, liver toxicity may occur. If you suspect an overdose, it is crucial to seek immediate emergency medical attention or contact a poison control center. Do not attempt to self-treat an overdose.
Can I drink alcohol while taking Zafirlukast?
The label does not describe a specific interaction with alcohol. Because zafirlukast is contraindicated in liver disease and liver injury has been reported with it, tell your prescriber honestly about your alcohol use so they can advise for your situation. (2)
Is Zafirlukast safe during pregnancy?
Zafirlukast's safety during pregnancy has not been definitively established, and it falls under a pregnancy category that requires careful consideration. It is essential to consult with your doctor if you are pregnant, planning to become pregnant, or breastfeeding before taking Zafirlukast. Your healthcare provider can assess the potential risks and benefits for your specific situation.
What is the mechanism of action of zafirlukast?
Zafirlukast is a selective leukotriene receptor antagonist (LTRA) that blocks the action of cysteinyl leukotrienes (LTC4, LTD4, and LTE4) at the CysLT1 receptor in the airway smooth muscle and other cells. This inhibition reduces bronchoconstriction, vascular permeability, and inflammation associated with asthma. (1)
What is the generic name of Zafirlukast?
The generic name is zafirlukast. It is sold under brand names including Accolate.
What class of drug is zafirlukast?
Zafirlukast is classed as: Leukotriene receptor antagonist (LTRA).
References
- Zafirlukast — Prescribing InformationU.S. National Library of Medicine, DailyMed · United States · accessed 2026-08-03 · source 1
- ZAFIRLUKAST tablets — prescribing information (Strides Pharma), updated 2026-03-16US FDA prescribing information via DailyMed · United States · dated 2026-03-16 · accessed 2026-08-08 · source 2
- ZAFIRLUKAST TABLET, COATED [STRIDES PHARMA SCIENCE LIMITED] — US prescribing information (DailyMed SPL)U.S. National Library of Medicine (DailyMed) · US · accessed 2026-08-14 · source 3
- Zafirlukast — patient drug information (MedlinePlus)U.S. National Library of Medicine (MedlinePlus) · US · accessed 2026-08-14 · source 4
- Zafirlukast — FDA approval record (Drugs@FDA ANDA212475)U.S. Food and Drug Administration · US · accessed 2026-08-14 · source 5
- zafirlukast — RxNorm normalized drug concept (RXCUI 114970)U.S. National Library of Medicine (RxNorm) · US · accessed 2026-08-14 · source 6
Brand names by country
Single-ingredient zafirlukast names are shown separately by country. Product availability, strengths, and supply rules can change; combination products are not included here.
Priority countries
Canada
- ACCOLATE