Fentanyl
Severe
Database
Drug interaction classified as: metabolism
Source: DDInter
Drug reference
Zafirlukast
Leukotriene Receptor Antagonist · Antiasthmatic
Leukotriene Receptor AntagonistAntiasthmatic
CDSCO approvedSchedule H
EXCRETION
—
not curated
INTERACTIONS
11 major
SEVERE in our sources
PREGNANCY
—
not curated
Top interactionssee all 12 →
- FentanylSevereDatabaseDDInter
- HalofantrineSevereDatabaseDDInter
- LeflunomideSevereDatabaseDDInter
- LemborexantSevereDatabaseDDInter
Mechanism
Zafirlukast is a selective cysteinyl leukotriene (CysLT) receptor antagonist. It prevents the activation of the CysLT1 receptor, thereby blocking the inflammatory effects mediated by leukotrienes. This action contributes to its efficacy in treating asthma. Additionally, zafirlukast is known to inhibit hepatic enzyme CYP2C9.
Indications
Mild to moderate asthmaBronchial asthmaProphylactic therapy of mild-to-moderate asthma (as alternatives to inhaled glucocorticoids)Aspirin-induced asthmaExercise-induced asthma
Dosing
- Adult
- Resistance to Warfarin. Some patients require >20 mg/day of warfarin to achieve a therapeutic INR. These patients often have excessive vitamin K intake from the diet or parenteral supplementation.. VKORC1 gene have been identified in some of these patients (Rost. <1.5 mg/day of warfarin to achieve an INR of 2-3.…
- Pediatric
- 5–11 yr 10 mg BD
Pharmacokinetics
Half-life
8–12 hours
Bioavailability
Well absorbed orally
Protein binding
Highly plasma protein bound
Metabolism
Metabolized by CYP2C9
Contraindications
- Not to be used for terminating asthma episodes
- No value in COPD
Side effects
Common
HeadacheRashes
Serious
- Eosinophilia (infrequent)
- Neuropathy (infrequent)
- Churg-Strauss syndrome (few cases reported)
Drug interactions
Halofantrine
Severe
Database
Clinical effect not specified
Source: DDInter
Leflunomide
Severe
Database
Clinical effect not specified
Source: DDInter
Lemborexant
Severe
Database
Clinical effect not specified
Source: DDInter
Levacetylmethadol
Severe
Database
Clinical effect not specified
Source: DDInter
Lomitapide
Severe
Database
Clinical effect not specified
Source: DDInter
Lonafarnib
Severe
Database
Clinical effect not specified
Source: DDInter
Mipomersen
Severe
Database
Clinical effect not specified
Source: DDInter
Pexidartinib
Severe
Database
Clinical effect not specified
Source: DDInter
Pimozide
Severe
Database
Clinical effect not specified
Source: DDInter
Teriflunomide
Severe
Database
Clinical effect not specified
Source: DDInter
Theophylline
Moderate
Database
Zafirlukast decreases the clearance of theophylline, which can increase its plasma concentration and risk of toxicity.
Monitor theophylline plasma concentrations and adjust theophylline dose as needed to avoid toxicity.
Source: DDInter
Related guidelines
Other Leukotriene Receptor Antagonist drugs
Ask House about Zafirlukast
Continue into a citation-backed clinical answer with the drug context already attached.
Sources: KD Tripathi 7e, Goodman & Gilman 14e, Harrison 22e·Verified: 2026-05-13 · House clinical team